Abstract

The nonlinear optical properties of silver-nanoparticle-decorated functionalized (hydrogen-induced reduction, exfoliated) multilayered graphene (AgNP/fG) composite have been investigated in the picosecond time scale by using the Z-scan technique. Drastic changes in the Z-scan profiles are obtained in AgNP/fG at 1064 nm as the profile flips from the behavior of strong saturable absorption (SA) to reverse saturable absorption (RSA) on increasing the incident intensity. On the other hand, in graphene, the effect of weaker SA is observed at low intensities, but it flips to RSA at higher incident intensities. The strong SA in the case of the composite has been attributed to the electronic interaction between graphene and silver nanoparticles. The metallic plasmonic transition has a contribution to the optical nonlinearity in AgNP/fG at 532 nm.

© 2012 Optical Society of America

1. INTRODUCTION

Graphene has attracted tremendous attention for its remarkable optical, electronic, and mechanical properties [1,2]. Graphene-based electronic and photonic devices have prompted a large number of investigations due to the high mobility of electrons [3,4]. It has been found that a single layer of graphene absorbs about 2.3% of light incident on it, and that multilayered graphene absorbs in the same proportion [5]. Because of its zero bandgap nature, absorption of electromagnetic radiation of any wavelength is possible [6]. Therefore, its optical properties can be exploited in a wide spectral range.

Pump–probe studies of epitaxial graphene have shown its saturable absorption (SA) behavior with ultrafast recovery time [7]. Sun et al. [8], demonstrated graphene-based mode locker, followed by studies on ultrafast pulse generation in the 1–1.5 μm region [1,9]. On the other hand, silver nanoparticles (AgNPs) have been found be useful in various applications, such as plasmon-controlled fluorescence [10], multiphoton plasmon-resonance microscopy [11], femtosecond filamentation, and supercontinuum generation [12]. Importantly, these features differ from those of the bulk silver and actually depend on the size and shape of the AgNPs [13].

The combination of the two classes of materials (graphene and nanoparticles) may lead to integration of the properties of the two components in new hybrid materials that possess important features for catalysis and nanotechnology [14]. An economical alternate for the semiconductor saturable absorber mirror technology [15] can be nanoparticle-graphene-embedded solid-state saturable absorber devices in the visible and IR region. In addition, adsorption of various organic molecules or metal nanoparticles onto the graphene surface results in an increase in the number of either electrons or holes through molecular charge transfer [16]. Such an induced charge transfer, in turn, can change the electronic and optical properties. This motivated us to study and compare the nonlinear properties of this hybrid material with the standard saturable absorber used in commercial lasers [17].

In contrast to planar graphene sheets, the wrinkled graphene has advantages in attaching the metal nanoparticles [18]. Therefore, in this paper, we report our studies on the optical nonlinear properties of such functionalized multilayer graphene (fG) and silver-decorated graphene (AgNP/fG) by using the Z-scan technique as a function of the wavelength and the intensity of the incident radiation. It is observed that the effect of SA becomes stronger at 1064 nm with silver decoration. With increasing the intensity, the effect of reverse saturable absorption (RSA) is observed, indicating a promise of optical limiting (OL).

2. EXPERIMENT

The experimental arrangement for the Z-scan is described in Fig. 1. The fundamental (1064 nm) and the second harmonic (532 nm) wavelengths of a picosecond Nd:YAG laser (Continuum Model YG601, 40 ps, 10 Hz) were used. The transmitted energy as a function of the sample position was measured at the far field with the help of a photodiode (Becker and Hickle, PDI-400), after focusing with a double convex lens of focal length 50 mm. A circular aperture of 1 mm diameter was used before the detector for the closed aperture (CA) Z-scan experiments. A large diameter double convex lens of focal length 200 mm replaced the circular aperture for the open aperture (OA) Z scan. The scattered light was measured by placing a detector at an angle of 25° to the beam axis. The beam was nearly Gaussian and we have considered the 86% beam criterion [19]. The radius of the beam waist (ωo) was 24 μm with the corresponding Rayleigh range (zR) of 2.0 mm. The sample thickness (1 mm) was less than the Rayleigh range to fulfill the thin sample approximation condition. 1 mg each of fG, AgNP/fG, and AgNPs in ethylene glycol were separately sonicated for 2 h for dispersion just before the experiment. The absorption spectra were recorded using a UV–visible spectrometer (JASCO, V-570) in a quartz cell of 1 mm thickness. Powder x-ray diffraction (XRD) studies were carried out using a PANalytical X’PERT Pro x-ray diffractometer with nickel-filtered Cu Kα radiation as the x-ray source. The pattern was recorded in the 2θ range of 5° to 90° with a step size of 0.016°. The Raman spectra were obtained with a WITEC Alpha 300 Confocal Raman system equipped with a Nd:YAG laser (532 nm) as the excitation source. The intensity was kept at the minimum to avoid laser-induced heating. Transmission electron microscopy (TEM) was carried out using a JEOL JEM-2010F microscope. Atomic force microscope (AFM) measurement was carried out using Dimension 3100 Nanoscope IV digital instruments in tapping mode.

 

Fig. 1. Experimental setup for Z-scan for measuring the nonlinear absorption and scattering. L, lens; S, sample; D1, D2, photodiodes.

Download Full Size | PPT Slide | PDF

A. Preparation of Functionalized Graphene

Graphene oxide was prepared by a modified Hummers’ method [20] and it was reduced to graphene by exfoliation in the presence of hydrogen gas [21]. Thus, synthesized multilayered graphene was functionalized in a 31 H2SO4HNO3 acid medium. 100 mg of (fG) was dispersed in deionized (DI) water first by ultrasonication and then by magnetic stirring for 5 h.

B. Preparation of Silver Nanoparticles

The AgNPs were prepared as follows. 150 mg of AgNO3 was dispersed in water by ultrasonication, followed by stirring. After 12 h, 20 ml of 0.1 M NaBH4 and 20 ml of 1 M NaOH were added to the above solution under dropwise stirring. The final solution was centrifuged and the supernatant was washed several times with water. Finally, the sample was dried in a vacuum oven at 80 °C for 10 h [22].

C. Preparation of Graphene Decorated with Silver Nanoparticles

To decorate the graphene with AgNPs, a known quantity of silver nitrate solution was added to the fG solution while stirring. After 24 h, 40 ml of reducing solution (mixture of NaBH4 and NaOH) was added drop by drop. The solution was washed with a copious amount of DI water and filtered to obtain the AgNP/fG. The filtrate was dried at 70 °C under vacuum [23].

3. THEORY

The transmission is calculated following a well-documented procedure for the Z-scan technique [24,25]. The input intensity (assumed to be Gaussian in nature with a beam waist ω0 and the pulse width τ0) is given as

I(z,r,t)=I0[ω0ω(z)]2exp[2r2ω(z)2]exp[t2τ02].
Here, I(z,r,t) is the intensity at the given sample position (z), radial position (r), and time (t). ω(z) [=ω0(1+z2/zR2)1/2] is the beam waist at z, and I0 is the on-axis peak irradiance of the beam at the focus. In the presence of two-photon absorption (2PA) and SA, the nonlinear absorption coefficient α(I) at a given incident intensity (I) is given as [26]
α(I)=αo1+I/Is+βI,
where α0 is the linear absorption coefficient, Is is the saturation intensity, and β is the 2PA coefficient. The differential equation that obeys the beam propagation in a thin nonlinear absorber is
dIdl=α(I)I.
For a given sample position z, the sample of length L is treated as composed of thin slices of thickness dl. Equation (3) is integrated numerically by using the Runge–Kutta method over l from 0 to L to obtain the output intensity at each z. This is followed by its integration over r from 0 to and over t from 0 to τ0 (40 ps) to get the transmitted energy Eout. The normalized transmission is obtained by dividing Eout by the linearly transmitted energy.

The expression for the normalized transmission of a material with 2PA is given by Eq. (4) [25,27]:

T(z)=m=0[q]m(1+m)3/2,
where q=βIzLeff, with Leff=[1exp(αoL)/αo]. Here, Leff is the effective length of the sample by taking the linear attenuation into account and Iz=Io/(1+z2/zR2) is the excitation intensity of the laser.

4. RESULTS AND DISCUSSION

A. Characterization of AgNP/fG

The absorption spectrum of fG (Fig. 2) shows the characteristic band at 5.4 eV, which corresponds to the ππ* transition of the aromatic CC bond. The absorption spectrum of AgNP/fG exhibits a broad peak at 2.9 eV, corresponding to the localized surface plasmon (LSP). The LSP peak of AgNP has been reported at 3.1 eV [28]. The small variation is attributed to the change in the dielectric environment and the electron density of AgNPs induced by the graphene sheets [29]. In AgNP/fG, the ππ* transition of the aromatic CC bond shifts to 4.7 eV, which has been attributed to the restoration of electronic conjugation within the graphene sheets [29].

 

Fig. 2. Absorption spectrum of (a) fG and (b) AgNP/fG in ethylene glycol. Curve (c) gives the Gaussian analysis of the plasmonic peak at 420 nm and curve (d) is the absorption spectrum of solvent.

Download Full Size | PPT Slide | PDF

Figure 3(a) shows the x-ray spectrum for AgNP/fG. The characteristic face centered peaks of AgNPs are present in the spectrum. The peaks at 38.2°, 44.3°, 64.4°, 77.5°, and 81.6° correspond, respectively, to the (111), (200), (220), (311), and (222) planes of AgNP, indicating its presence. A small peak around 26.6° represents the hexagonal structure of graphene. The particle size of AgNPs, calculated using Scherer’s equation for the 38.2° XRD peak, is 5nm.

 

Fig. 3. (a) XRD pattern and (b) Raman spectrum of AgNP/fG and fG.

Download Full Size | PPT Slide | PDF

The Raman spectra can reveal the presence of electronic interaction between the graphene and AgNPs [30]. The Raman spectrum of graphene shows characteristic D (1356cm1) and G (1588cm1) bands. While the G band corresponds to the vibration of the sp2 bonded carbon atoms, the D band is a defect-induced feature that is absent in defect-free samples. The 2D band (second order of the D band) at 2679cm1 [shown in the inset of Fig. 3(b)] is weak and smeared along with the D+G band. This is due to the fact that the 2D band is very sensitive to the stacking order along the c axis, as well as on the number of layers. Thus it indicates toward the randomly arranged and disordered multilayered graphene sheets in the present case. In the case of AgNP/fG [Fig. 3(b)], the positions of the D band (1375cm1), the G band (1590cm1), and the 2D band (2690cm1) show small (520cm1) shifts, which confirms the silver decoration of graphene [16,31]. The intensity ratio of the D band to the G band, (ID/IG) is a measure of the disorder in the sample [30]. The ID/IG ratios obtained for fG and AgNP/fG are 0.99 and 1.07, respectively, indicating more disorder in the latter. The intensity ratio (I2D/IG) of the 2D band to the G band for AgNP/fG (0.73) is smaller than that for fG (0.91), confirming the doping [32].

The TEM image of the AgNP/fG was recorded to determine the morphology and presence of AgNPs. Figure 4(a) shows the uniformly distributed AgNPs on graphene sheets. From a magnified image of AgNPs [Fig. 4(b)], the average size of the AgNPs can be seen as 5nm. The wrinkled morphology of exfoliated graphene using AFM has been reported earlier [21].

 

Fig. 4. (a) TEM image of graphene composite. The encircled area shows the nearly uniform distribution of AgNPs. (b) Magnified image used for size determination of AgNPs.

Download Full Size | PPT Slide | PDF

B. Z-Scan Profiles at 1064 nm

The OA Z-scan profiles were recorded at 1064 nm for fG, AgNP, and AgNP/fG samples for a concentration of 1mg/ml. The Z-dependent normalized transmission through AgNP/fG fG, and AgNPs for various intensity values at focus are shown in Figs. 5(a)(c), respectively. The normalized transmission for AgNP/fG at lower intensities (5GW/cm2 and 14GW/cm2) shows a peak at the focus, indicating the effect of SA. With an increase in the intensity, the Z-scan profiles show a dip at the center, indicating a flip from the behavior of SA to RSA. The profiles at higher intensities (24GW/cm2, 36GW/cm2, and 52GW/cm2) are composed of three distinctive regions, namely, (i) linear absorption far from the focus (low intensity), (ii) SA near the focus (medium intensity), and (iii) RSA at the focus (high intensity). The OA Z-scan measurement for the fG [Fig. 5(b)], however, shows weak SA at 14GW/cm2. This is consistent with the earlier report at 1040 nm, in which SA was observed beyond 4MW/cm2 under femtosecond pumping [9]. The weaker SA in the present case is attributed to the wrinkled nature of the multilayer graphene. With an increase in the intensity to 24GW/cm2 and 36GW/cm2, it exhibits the effect of RSA. Similar OA measurements carried out for AgNPs [Fig. 5(c)] did not contain any signature of SA. The observed stronger behavior of SA for the composite, therefore, is due to the interaction between AgNPs and fG. The measurement for the pure solvent was also carried out under identical experimental conditions to ensure that the observed nonlinearity is due only to the samples. The scattered light measurements show that, at lower pump intensities, there was no scattering, as compared to that at higher pump intensities, where nonlinear scattering (105 times weaker than the signal) was observed when the samples passed through the focus. This indicates that, at higher incident flux, the thermal contribution of the nonlinear scattering is present, similar to that reported in the case of nanosecond pumping [2].

 

Fig. 5. OA Z-scan profile of the (a) AgNP/fG, (b) fG, and (c) AgNPs at 1064 nm at different pump energies with constant concentration 1mg/ml. Inset of (a) shows the ratio of CA to OA profiles (with error bars of 10%) at an intensity of 45GW/cm2. (d) OA Z-scan profile of SA IR26 in 1,2 di-chloroethane.

Download Full Size | PPT Slide | PDF

The observed Z-scan profiles are fitted using the method described in Section 3, by keeping Is and β as free parameters. The presence of contributions of both SA and RSA necessitates the data of fG and AgNP/fG to be fitted with Eq. (3), while Eq. (4) is used for AgNPs in the absence of SA. The obtained values of Is and β for these samples are given in Table 1. The low-energy Z-scan profile of AgNP/fG is similar to the standard SA IR26, as shown in Fig. 5(d).

Tables Icon

Table 1. Optical Nonlinear Properties of AgNP/fG, fG, and AgNPs

The CA Z-scan measurement at the intensity of 45GW/cm2 was carried out for the AgNP/fG composite. The inset of Fig. 5(a) shows the normalized transmission as a function of the distance from the focus. The profile clearly shows a valley–peak structure, indicating a positive nonlinear refractive index. The real part of χ(3) was obtained as 3×1020m2/V2 from this profile. The pure refractive contribution was obtained by taking the ratio of CA and OA profiles at 45GW/cm2. It can be seen that the data exhibit large error at the peak. The asymmetric nature of the profile is due to the dominant contribution of RSA along with that of weak SA at higher incident flux.

C. Z-Scan Profiles at 532 nm

At 532 nm, the absorption spectrum of AgNP/fG (Fig. 2) shows considerable absorption as compared to that at 1064 nm. The normalized transmission for AgNP/fG in Fig. 6(a) at lower intensity of 6GW/cm2 shows the behavior of SA. With increase in the intensity to 13GW/cm2, the profile shifts to RSA. The OA Z-scan measurements for AgNPs and fG were also performed at similar pump energies. The Z-scan profile of fG [Fig. 6(b)] shows linear absorption up to the intensity of 13GW/cm2. With increase in the intensity to 27GW/cm2, the effect of SA is observed. With further increase in the intensity to 56GW/cm2, the profile exhibits RSA, similar to that observed in AgNP/fG. On the other hand, the AgNPs [Fig. 6(c)] shows very weak SA at lower intensity (13GW/cm2). This corresponds to the bleaching of the plasmonic band. With increase in the intensity the contribution of RSA is observed. The obtained values Is and β are also given in Table 1, along with the available values in literature [33]. It can be seen that the Is value of AgNP/fG is lower by 1 order as compared to graphene. The interaction between fG and AgNPs causes the Is to be lower than that of fG and also allows us to achieve SA at lower intensities. In the present case, the obtained value of β for graphene matches well with that reported in the literature [34].

 

Fig. 6. OA Z-scan profile of (a) AgNP/fG, (b) fG, and (c) AgNPs at 532 nm at different pump energies with constant concentration of 1mg/ml.

Download Full Size | PPT Slide | PDF

D. Mechanism of Nonlinear Absorption at 1064 and 532 nm

1. Graphene

Pure graphene has zero bandgap (Fig. 7) and the Fermi level is at the intersection of V-shaped conduction band (CB) and the valence band (VB) at the K point of the Brillouin zone. Absorption of light of any wavelength is thus possible. The high-intensity excitation creates large transient populations of carriers in the VB and the CB. Following this, the nonequilibrium carrier distributions in the CB and VB undergo ultrafast interband relaxation through nondissipative carrier–carrier scattering and carrier–phonon coupling within 150 fs [7]. This is followed by the electron-hole recombination process to attain the equilibrium electron and hole distribution within 2ps [7]. The relaxation times are shorter than the pulse duration (40 ps) used in the present experiments. Therefore, during the pulse at lower intensities, the carrier populations thermalize in each band. With increasing the intensity, more electron–hole pairs are generated and cause the states near the edge of the CB to fill. This blocks further absorption, which results in the SA behavior at both the wavelengths at lower intensity. With further increase in the intensity with the availability of the large photon flux, 2PA takes place, resulting in the effect of RSA, as indicated in Fig. 7. This observation is similar to that observed in graphene oxide [35]. At high intensities, the scattering measurements were similar to that described in Subsection 4.B, indicating minor additional contribution of nonlinear scattering to RSA. Studies on carbon black [36] and carbon nanotubes (CNTs) [37] have revealed the mechanisms of nonlinear scattering as the formation of the bubble clouds or microplasmas.

 

Fig. 7. Energy diagram of the metal–graphene interface and resulting Fermi level with respect to the Dirac point. Fermi level EF shifts due to the charge transfer, the work function of the metal (φM=5.0eV), and graphene (φG=4.5eV) are also indicated. ΔW is caused by the charge built up at the interface.

Download Full Size | PPT Slide | PDF

2. Silver Nanoparticles

The localized surface plasmon band of AgNPs at 420 nm (2.9 eV) is situated below the interband transition (d to s-p band, with 4 eV). To understand the mechanism at 532 nm, Gaussian analysis of the absorption spectrum of the composite (Fig. 2) was done. It can be seen that there is a direct excitation to the localized surface plasmonic band near 532 nm (2.3 eV). The observed SA at low intensity results from the intraband electron excitation within the CB, leading to the ground-state bleaching of the plasmon band. With increase in the intensity, the transient absorption from free carriers becomes significant, resulting in RSA. In addition, the photoejection of the electrons can occur at higher laser intensities due to multiphoton absorption [38], leading to RSA. However, the interband transition (d to s-p band) due to 2PA can also take place at 532 nm [39]. At 1064 nm, however, the RSA is observed only after pumping with high intensity, which can only be attributed to 2PA to the edge of the intraband following the aforementioned mechanism.

3. Silver-Nanoparticle-Decorated Graphene

As suggested by Rao and co-workers [16], when in physical contact, electron transfer takes place from graphene to the AgNPs to achieve a common Fermi level (Fig. 7). Under illumination, electrons from the VB are excited to the CB. The first principles calculations [16] show the possibility of intermediate AgNP metal states that are flat and extend into graphene. However, the excited electrons have higher probability of transferring to the metal states across the surface than to the graphene VBs owing to considerably larger density of states in the metal. The excited carriers from graphene can transfer to those metal states before returning to the VB. Besides providing long lifetimes, the transferred electrons eventually return to graphene, but the time scale is much larger than the pulse width of the laser. Since the carriers are excited faster than their return to the original state, the bleaching of the ground state takes place, resulting in strong SA behavior. With increase in the intensity, the RSA dominates over the SA, as shown in Figs. 5(a) and 6(a). The observed RSA at 1064 nm can be attributed due to the similar mechanism of nonlinear scattering and 2PA, as in the case of fG. Besides the above mentioned mechanism, at the wavelength of 532 nm, the observed behavior can be understood due to the LSP of the AgNP.

E. Optical Limiting

To study the OL behavior of the system, we used the Z-scan curves from Fig. 5 and plotted the normalized transmittance as a function of the input intensity. The so-obtained OL curves for AgNP/fG, fG, and AgNPs are shown in Fig. 8 at 1064 nm. For fG (lower curve), the value of normalized transmittance falls near unity at lower intensity, indicating the linear absorption. With the increase in the intensity, the transmittance shows a weak SA effect, followed by a decrease, indicating the OL behavior. In the AgNP/fG system, the normalized transmittance is more than unity for the incident intensity range of 2030GW/cm2, indicating the dominant effect of SA. With increase in the incident intensity, the transmittance decreases sharply, indicating strong OL. The three regions of the absorption discussed earlier for the AgNP/fG system are also seen in Fig. 5(a). The AgNPs [Fig. 5(c)] do not show any significant limiting. It is to be noted that carbon-based materials, such as CNTs and carbon black, are strong optical limiters due to the nonlinear scattering in the nanosecond regime [36,37].

 

Fig. 8. OL properties of AgNP/fG, fG, and AgNPs at 1064 nm.

Download Full Size | PPT Slide | PDF

5. CONCLUSIONS

The nonlinear optical properties of silver-decorated multilayered wrinkled graphene have been studied by using the Z-scan technique at 1064 and 532 nm at the picosecond time scale. The intensity-dependent studies on fG at 1064 nm exhibit a weak SA, followed by RSA at higher intensities. However, the AgNP/fG has strong SA and RSA effects at low and high intensities, respectively. This indicates that the saturable intensity in multilayer graphene can be modified by doping with metal nanoparticles. The appearance of stronger SA in AgNP/fG composite is attributed to the electronic interaction between the AgNP and fG. The OL studies show that the composite is stable for applications with higher threshold intensities of 40GW/cm2. At the wavelength of 532 nm, the observed behavior can be understood due to the combined effects of graphene and LSP of the silver nanoparticles.

ACKNOWLEDGMENTS

We thank the Council of Scientific and Industrial Research (CSIR) New Delhi for financial assistance. We thank Dr. Srini Krishnamurthy for the critical reading of the manuscript.

REFERENCES

1. F. Bonaccorso, Z. Sun, T. Hasan, and A. C. Ferrari, “Graphene photonics and optoelectronics,” Nat. Photon. 4, 611–622 (2010). [CrossRef]  

2. J. Wang, Y. Hernandez, M. Lotya, J. N. Coleman, and W. J. Blau, “Broadband nonlinear optical response of graphene dispersions,” Adv. Mater. 21, 2430–2435 (2009). [CrossRef]  

3. J. R. Williams, L. DiCarlo, and C. M. Marcus, “Quantum hall effect in a gate-controlled p-n junction of graphene,” Science 317, 638–641 (2007). [CrossRef]  

4. F. Rana, “Graphene terahertz plasmon oscillators,” IEEE Trans. Nanotechnol. 7, 91–99 (2008). [CrossRef]  

5. R. R. Nair, P. Blake, A. N. Grigorenko, K. S. Novoselov, T. J. Booth, T. Stauber, N. M. R. Peres, and A. K. Geim, “Fine structure constant defines visual transparency of graphene,” Science 320, 1308 (2008). [CrossRef]  

6. K. S. Novoselov, A. K. Geim, S. V. Morozov, D. Jiang, Y. Zhang, S. V. Dubonos, I. V. Grigorieva, and A. A. Firsov, “Electric field effect in atomically thin carbon films,” Science 306, 666–669 (2004). [CrossRef]  

7. J. M. Dawlaty, S. Shivaraman, M. Chandrashekhar, F. Rana, and M. G. Spencer, “Measurement of ultrafast carrier dynamics in epitaxial graphene,” Appl. Phys. Lett. 92, 042116 (2008). [CrossRef]  

8. Z. Sun, T. Hasan, F. Torrisi, D. Popa, G. Privitera, F. Wang, F. Bonaccorso, D. M. Basko, and A. C. Ferrari, “Graphene mode-locked ultrafast laser,” ACS Nano 4, 803–810 (2010). [CrossRef]  

9. W. D. Tan, C. Y. Su, R. J. Knize, G. Q. Xie, L. J. Li, and D. Y. Tang, “Mode locking of ceramic Nd:yttrium aluminum garnet with graphene as a saturable absorber,” Appl. Phys. Lett. 96, 031106 (2010). [CrossRef]  

10. J. Lakowicz, “Plasmonics in biology and plasmon-controlled fluorescence,” Plasmonics 1, 5–33 (2006). [CrossRef]  

11. D. Yelin, D. Oron, S. Thiberge, E. Moses, and Y. Silberberg, “Multiphoton plasmon-resonance microscopy,” Opt. Express 11, 1385–1391 (2003). [CrossRef]  

12. C. Wang, Y. Fu, Z. Zhou, Y. Cheng, and Z. Xu, “Femtosecond filamentation and supercontinuum generation in silver-nanoparticle-doped water,” Appl. Phys. Lett. 90, 181119 (2007). [CrossRef]  

13. A. P. Alivisatos, “Semiconductor clusters, nanocrystals, and quantum dots,” Science 271, 933–937 (1996). [CrossRef]  

14. G. G. Wildgoose, C. E. Banks, and R. G. Compton, “Metal nanoparticles and related materials supported on carbon nanotubes: methods and applications,” Small 2, 182–193 (2006). [CrossRef]  

15. D. J. H. C. Maas, A. R. Bellancourt, M. Hoffmann, B. Rudin, Y. Barbarin, M. Golling, T. Südmeyer, and U. Keller, “Growth parameter optimization for fast quantum dot SESAMs,” Opt. Express 16, 18646–18656 (2008). [CrossRef]  

16. K. S. Subrahmanyam, A. K. Manna, S. K. Pati, and C. N. R. Rao, “A study of graphene decorated with metal nanoparticles,” Chem. Phys. Lett. 497, 70–75 (2010). [CrossRef]  

17. B. S. Kalanoor and P. B. Bisht, “Wavelength dependent resonant nonlinearities in a standard saturable absorber IR26 on picosecond time scale,” Opt. Commun. 283, 4059–4063 (2010). [CrossRef]  

18. G. Goncalves, P. A. A. P. Marques, C. M. Granadeiro, H. I. S. Nogueira, M. K. Singh, and J. Grácio, “Surface modification of graphene nanosheets with gold nanoparticles: the role of oxygen moieties at graphene surface on gold nucleation and growth,” Chem. Mater. 21, 4796–4802 (2009). [CrossRef]  

19. A. E. Siegman, Lasers (University Science, 1986).

20. W. S. Hummers and R. E. Offeman, “Preparation of graphitic oxide,” J. Am. Chem. Soc. 80, 1339–1339 (1958). [CrossRef]  

21. A. Kaniyoor, T. T. Baby, and S. Ramaprabhu, “Graphene synthesis via hydrogen induced low temperature exfoliation of graphite oxide,” J. Mater. Chem. 20, 8467–8469 (2010). [CrossRef]  

22. J. A. Creighton, C. G. Blatchford, and M. G. Albrecht, “Plasma resonance enhancement of Raman scattering by pyridine adsorbed on silver or gold sol particles of size comparable to the excitation wavelength,” J. Chem. Soc. Faraday Trans. 2 75, 790–798 (1979). [CrossRef]  

23. T. T. Baby and S. Ramaprabhu, “Synthesis and nanofluid application of silver nanoparticles decorated graphene,” J. Mater. Chem. 21, 9702–9709 (2011). [CrossRef]  

24. T.-H. Wei and T.-H. Huang, “A study of photophysics using the Z-scan technique: lifetime determination for high-lying excited states,” Opt. Quantum Electron. 28, 1495–1508 (1996). [CrossRef]  

25. M. Sheik-Bahae, A. A. Said, T. H. Wei, D. J. Hagan, and E. W. Van Stryland, “Sensitive measurement of optical nonlinearities using a single beam,” IEEE J. Quantum Electron. 26, 760–769 (1990). [CrossRef]  

26. Y. Gao, X. Zhang, Y. Li, H. Liu, Y. Wang, Q. Chang, W. Jiao, and Y. Song, “Saturable absorption and reverse saturable absorption in platinum nanoparticles,” Opt. Commun. 251, 429–433 (2005). [CrossRef]  

27. J. He, Y. Qu, H. Li, J. Mi, and W. Ji, “Three-photon absorption in ZnO and ZnS crystals,” Opt. Express 13, 9235–9247 (2005). [CrossRef]  

28. P. Mulvaney, “Surface plasmon spectroscopy of nanosized metal particles,” Langmuir 12, 788–800 (1996). [CrossRef]  

29. D. Li and R. B. Kaner, “Graphene-based materials,” Science 320, 1170–1171 (2008). [CrossRef]  

30. B. Das, R. Voggu, C. S. Rout, and C. N. R. Rao, “Changes in the electronic structure and properties of graphene induced by molecular charge-transfer,” Chem. Commun. 44, 5155–5157 (2008). [CrossRef]  

31. Z. Zhang, F. Xu, W. Yang, M. Guo, X. Wang, B. Zhang, and J. Tang, “A facile one-pot method to high-quality Ag-graphene composite nanosheets for efficient surface-enhanced Raman scattering,” Chem. Commun. 47, 6440–6442 (2011). [CrossRef]  

32. A. Das, S. Pisana, B. Chakraborty, S. Piscanec, S. K. Saha, U. V. Waghmare, K. S. Novoselov, H. R. Krishnamurthy, A. K. Geim, A. C. Ferrari, and A. K. Sood, “Monitoring dopants by Raman scattering in an electrochemically top-gated graphene transistor,” Nat. Nanotechnol. 3, 210–215 (2008). [CrossRef]  

33. R. A. Ganeev and et al., “Nonlinear susceptibilities, absorption coefficients and refractive indices of colloidal metals,” J. Phys. D 34, 1602–1611 (2001). [CrossRef]  

34. Z. Liu, Y. Wang, X. Zhang, Y. Xu, Y. Chen, and J. Tian, “Nonlinear optical properties of graphene oxide in nanosecond and picosecond regimes,” Appl. Phys. Lett. 94, 021902 (2009). [CrossRef]  

35. S. Kumar, M. Anija, N. Kamaraju, K. S. Vasu, K. S. Subrahmanyam, A. K. Sood, and C. N. R. Rao, “Femtosecond carrier dynamics and saturable absorption in graphene suspensions,” Appl. Phys. Lett. 95, 191911 (2009). [CrossRef]  

36. D. Vincent, S. Petit, and S. L. Chin, “Optical limiting studies in a carbon-black suspension for subnanosecond and subpicosecond laser pulses,” Appl. Opt. 41, 2944–2946 (2002). [CrossRef]  

37. X. Sun, Y. Xiong, P. Chen, J. Lin, W. Ji, J. H. Lim, S. S. Yang, D. J. Hagan, and E. W. Van Stryland, “Investigation of an optical limiting mechanism in multiwalled carbon nanotubes,” Appl. Opt. 39, 1998–2001 (2000). [CrossRef]  

38. P. V. Kamat, M. Flumiani, and G. V. Hartland, “Picosecond dynamics of silver nanoclusters. Photoejection of electrons and fragmentation,” J. Phys. Chem. B 102, 3123–3128 (1998). [CrossRef]  

39. U. Gurudas, E. Brooks, D. M. Bubb, S. Heiroth, T. Lippert, and A. Wokaun, “Saturable and reverse saturable absorption in silver nanodots at 532 nm using picosecond laser pulses,” J. Appl. Phys. 104, 073107 (2008). [CrossRef]  

References

  • View by:
  • |
  • |
  • |

  1. F. Bonaccorso, Z. Sun, T. Hasan, and A. C. Ferrari, “Graphene photonics and optoelectronics,” Nat. Photon. 4, 611–622 (2010).
    [CrossRef]
  2. J. Wang, Y. Hernandez, M. Lotya, J. N. Coleman, and W. J. Blau, “Broadband nonlinear optical response of graphene dispersions,” Adv. Mater. 21, 2430–2435 (2009).
    [CrossRef]
  3. J. R. Williams, L. DiCarlo, and C. M. Marcus, “Quantum hall effect in a gate-controlled p-n junction of graphene,” Science 317, 638–641 (2007).
    [CrossRef]
  4. F. Rana, “Graphene terahertz plasmon oscillators,” IEEE Trans. Nanotechnol. 7, 91–99 (2008).
    [CrossRef]
  5. R. R. Nair, P. Blake, A. N. Grigorenko, K. S. Novoselov, T. J. Booth, T. Stauber, N. M. R. Peres, and A. K. Geim, “Fine structure constant defines visual transparency of graphene,” Science 320, 1308 (2008).
    [CrossRef]
  6. K. S. Novoselov, A. K. Geim, S. V. Morozov, D. Jiang, Y. Zhang, S. V. Dubonos, I. V. Grigorieva, and A. A. Firsov, “Electric field effect in atomically thin carbon films,” Science 306, 666–669 (2004).
    [CrossRef]
  7. J. M. Dawlaty, S. Shivaraman, M. Chandrashekhar, F. Rana, and M. G. Spencer, “Measurement of ultrafast carrier dynamics in epitaxial graphene,” Appl. Phys. Lett. 92, 042116 (2008).
    [CrossRef]
  8. Z. Sun, T. Hasan, F. Torrisi, D. Popa, G. Privitera, F. Wang, F. Bonaccorso, D. M. Basko, and A. C. Ferrari, “Graphene mode-locked ultrafast laser,” ACS Nano 4, 803–810 (2010).
    [CrossRef]
  9. W. D. Tan, C. Y. Su, R. J. Knize, G. Q. Xie, L. J. Li, and D. Y. Tang, “Mode locking of ceramic Nd:yttrium aluminum garnet with graphene as a saturable absorber,” Appl. Phys. Lett. 96, 031106 (2010).
    [CrossRef]
  10. J. Lakowicz, “Plasmonics in biology and plasmon-controlled fluorescence,” Plasmonics 1, 5–33 (2006).
    [CrossRef]
  11. D. Yelin, D. Oron, S. Thiberge, E. Moses, and Y. Silberberg, “Multiphoton plasmon-resonance microscopy,” Opt. Express 11, 1385–1391 (2003).
    [CrossRef]
  12. C. Wang, Y. Fu, Z. Zhou, Y. Cheng, and Z. Xu, “Femtosecond filamentation and supercontinuum generation in silver-nanoparticle-doped water,” Appl. Phys. Lett. 90, 181119 (2007).
    [CrossRef]
  13. A. P. Alivisatos, “Semiconductor clusters, nanocrystals, and quantum dots,” Science 271, 933–937 (1996).
    [CrossRef]
  14. G. G. Wildgoose, C. E. Banks, and R. G. Compton, “Metal nanoparticles and related materials supported on carbon nanotubes: methods and applications,” Small 2, 182–193 (2006).
    [CrossRef]
  15. D. J. H. C. Maas, A. R. Bellancourt, M. Hoffmann, B. Rudin, Y. Barbarin, M. Golling, T. Südmeyer, and U. Keller, “Growth parameter optimization for fast quantum dot SESAMs,” Opt. Express 16, 18646–18656 (2008).
    [CrossRef]
  16. K. S. Subrahmanyam, A. K. Manna, S. K. Pati, and C. N. R. Rao, “A study of graphene decorated with metal nanoparticles,” Chem. Phys. Lett. 497, 70–75 (2010).
    [CrossRef]
  17. B. S. Kalanoor and P. B. Bisht, “Wavelength dependent resonant nonlinearities in a standard saturable absorber IR26 on picosecond time scale,” Opt. Commun. 283, 4059–4063 (2010).
    [CrossRef]
  18. G. Goncalves, P. A. A. P. Marques, C. M. Granadeiro, H. I. S. Nogueira, M. K. Singh, and J. Grácio, “Surface modification of graphene nanosheets with gold nanoparticles: the role of oxygen moieties at graphene surface on gold nucleation and growth,” Chem. Mater. 21, 4796–4802 (2009).
    [CrossRef]
  19. A. E. Siegman, Lasers (University Science, 1986).
  20. W. S. Hummers and R. E. Offeman, “Preparation of graphitic oxide,” J. Am. Chem. Soc. 80, 1339–1339 (1958).
    [CrossRef]
  21. A. Kaniyoor, T. T. Baby, and S. Ramaprabhu, “Graphene synthesis via hydrogen induced low temperature exfoliation of graphite oxide,” J. Mater. Chem. 20, 8467–8469 (2010).
    [CrossRef]
  22. J. A. Creighton, C. G. Blatchford, and M. G. Albrecht, “Plasma resonance enhancement of Raman scattering by pyridine adsorbed on silver or gold sol particles of size comparable to the excitation wavelength,” J. Chem. Soc. Faraday Trans. 2 75, 790–798 (1979).
    [CrossRef]
  23. T. T. Baby and S. Ramaprabhu, “Synthesis and nanofluid application of silver nanoparticles decorated graphene,” J. Mater. Chem. 21, 9702–9709 (2011).
    [CrossRef]
  24. T.-H. Wei and T.-H. Huang, “A study of photophysics using the Z-scan technique: lifetime determination for high-lying excited states,” Opt. Quantum Electron. 28, 1495–1508 (1996).
    [CrossRef]
  25. M. Sheik-Bahae, A. A. Said, T. H. Wei, D. J. Hagan, and E. W. Van Stryland, “Sensitive measurement of optical nonlinearities using a single beam,” IEEE J. Quantum Electron. 26, 760–769 (1990).
    [CrossRef]
  26. Y. Gao, X. Zhang, Y. Li, H. Liu, Y. Wang, Q. Chang, W. Jiao, and Y. Song, “Saturable absorption and reverse saturable absorption in platinum nanoparticles,” Opt. Commun. 251, 429–433 (2005).
    [CrossRef]
  27. J. He, Y. Qu, H. Li, J. Mi, and W. Ji, “Three-photon absorption in ZnO and ZnS crystals,” Opt. Express 13, 9235–9247 (2005).
    [CrossRef]
  28. P. Mulvaney, “Surface plasmon spectroscopy of nanosized metal particles,” Langmuir 12, 788–800 (1996).
    [CrossRef]
  29. D. Li and R. B. Kaner, “Graphene-based materials,” Science 320, 1170–1171 (2008).
    [CrossRef]
  30. B. Das, R. Voggu, C. S. Rout, and C. N. R. Rao, “Changes in the electronic structure and properties of graphene induced by molecular charge-transfer,” Chem. Commun. 44, 5155–5157 (2008).
    [CrossRef]
  31. Z. Zhang, F. Xu, W. Yang, M. Guo, X. Wang, B. Zhang, and J. Tang, “A facile one-pot method to high-quality Ag-graphene composite nanosheets for efficient surface-enhanced Raman scattering,” Chem. Commun. 47, 6440–6442 (2011).
    [CrossRef]
  32. A. Das, S. Pisana, B. Chakraborty, S. Piscanec, S. K. Saha, U. V. Waghmare, K. S. Novoselov, H. R. Krishnamurthy, A. K. Geim, A. C. Ferrari, and A. K. Sood, “Monitoring dopants by Raman scattering in an electrochemically top-gated graphene transistor,” Nat. Nanotechnol. 3, 210–215 (2008).
    [CrossRef]
  33. R. A. Ganeev and et al., “Nonlinear susceptibilities, absorption coefficients and refractive indices of colloidal metals,” J. Phys. D 34, 1602–1611 (2001).
    [CrossRef]
  34. Z. Liu, Y. Wang, X. Zhang, Y. Xu, Y. Chen, and J. Tian, “Nonlinear optical properties of graphene oxide in nanosecond and picosecond regimes,” Appl. Phys. Lett. 94, 021902 (2009).
    [CrossRef]
  35. S. Kumar, M. Anija, N. Kamaraju, K. S. Vasu, K. S. Subrahmanyam, A. K. Sood, and C. N. R. Rao, “Femtosecond carrier dynamics and saturable absorption in graphene suspensions,” Appl. Phys. Lett. 95, 191911 (2009).
    [CrossRef]
  36. D. Vincent, S. Petit, and S. L. Chin, “Optical limiting studies in a carbon-black suspension for subnanosecond and subpicosecond laser pulses,” Appl. Opt. 41, 2944–2946 (2002).
    [CrossRef]
  37. X. Sun, Y. Xiong, P. Chen, J. Lin, W. Ji, J. H. Lim, S. S. Yang, D. J. Hagan, and E. W. Van Stryland, “Investigation of an optical limiting mechanism in multiwalled carbon nanotubes,” Appl. Opt. 39, 1998–2001 (2000).
    [CrossRef]
  38. P. V. Kamat, M. Flumiani, and G. V. Hartland, “Picosecond dynamics of silver nanoclusters. Photoejection of electrons and fragmentation,” J. Phys. Chem. B 102, 3123–3128 (1998).
    [CrossRef]
  39. U. Gurudas, E. Brooks, D. M. Bubb, S. Heiroth, T. Lippert, and A. Wokaun, “Saturable and reverse saturable absorption in silver nanodots at 532 nm using picosecond laser pulses,” J. Appl. Phys. 104, 073107 (2008).
    [CrossRef]

2011

T. T. Baby and S. Ramaprabhu, “Synthesis and nanofluid application of silver nanoparticles decorated graphene,” J. Mater. Chem. 21, 9702–9709 (2011).
[CrossRef]

Z. Zhang, F. Xu, W. Yang, M. Guo, X. Wang, B. Zhang, and J. Tang, “A facile one-pot method to high-quality Ag-graphene composite nanosheets for efficient surface-enhanced Raman scattering,” Chem. Commun. 47, 6440–6442 (2011).
[CrossRef]

2010

A. Kaniyoor, T. T. Baby, and S. Ramaprabhu, “Graphene synthesis via hydrogen induced low temperature exfoliation of graphite oxide,” J. Mater. Chem. 20, 8467–8469 (2010).
[CrossRef]

F. Bonaccorso, Z. Sun, T. Hasan, and A. C. Ferrari, “Graphene photonics and optoelectronics,” Nat. Photon. 4, 611–622 (2010).
[CrossRef]

Z. Sun, T. Hasan, F. Torrisi, D. Popa, G. Privitera, F. Wang, F. Bonaccorso, D. M. Basko, and A. C. Ferrari, “Graphene mode-locked ultrafast laser,” ACS Nano 4, 803–810 (2010).
[CrossRef]

W. D. Tan, C. Y. Su, R. J. Knize, G. Q. Xie, L. J. Li, and D. Y. Tang, “Mode locking of ceramic Nd:yttrium aluminum garnet with graphene as a saturable absorber,” Appl. Phys. Lett. 96, 031106 (2010).
[CrossRef]

K. S. Subrahmanyam, A. K. Manna, S. K. Pati, and C. N. R. Rao, “A study of graphene decorated with metal nanoparticles,” Chem. Phys. Lett. 497, 70–75 (2010).
[CrossRef]

B. S. Kalanoor and P. B. Bisht, “Wavelength dependent resonant nonlinearities in a standard saturable absorber IR26 on picosecond time scale,” Opt. Commun. 283, 4059–4063 (2010).
[CrossRef]

2009

G. Goncalves, P. A. A. P. Marques, C. M. Granadeiro, H. I. S. Nogueira, M. K. Singh, and J. Grácio, “Surface modification of graphene nanosheets with gold nanoparticles: the role of oxygen moieties at graphene surface on gold nucleation and growth,” Chem. Mater. 21, 4796–4802 (2009).
[CrossRef]

J. Wang, Y. Hernandez, M. Lotya, J. N. Coleman, and W. J. Blau, “Broadband nonlinear optical response of graphene dispersions,” Adv. Mater. 21, 2430–2435 (2009).
[CrossRef]

Z. Liu, Y. Wang, X. Zhang, Y. Xu, Y. Chen, and J. Tian, “Nonlinear optical properties of graphene oxide in nanosecond and picosecond regimes,” Appl. Phys. Lett. 94, 021902 (2009).
[CrossRef]

S. Kumar, M. Anija, N. Kamaraju, K. S. Vasu, K. S. Subrahmanyam, A. K. Sood, and C. N. R. Rao, “Femtosecond carrier dynamics and saturable absorption in graphene suspensions,” Appl. Phys. Lett. 95, 191911 (2009).
[CrossRef]

2008

A. Das, S. Pisana, B. Chakraborty, S. Piscanec, S. K. Saha, U. V. Waghmare, K. S. Novoselov, H. R. Krishnamurthy, A. K. Geim, A. C. Ferrari, and A. K. Sood, “Monitoring dopants by Raman scattering in an electrochemically top-gated graphene transistor,” Nat. Nanotechnol. 3, 210–215 (2008).
[CrossRef]

D. J. H. C. Maas, A. R. Bellancourt, M. Hoffmann, B. Rudin, Y. Barbarin, M. Golling, T. Südmeyer, and U. Keller, “Growth parameter optimization for fast quantum dot SESAMs,” Opt. Express 16, 18646–18656 (2008).
[CrossRef]

U. Gurudas, E. Brooks, D. M. Bubb, S. Heiroth, T. Lippert, and A. Wokaun, “Saturable and reverse saturable absorption in silver nanodots at 532 nm using picosecond laser pulses,” J. Appl. Phys. 104, 073107 (2008).
[CrossRef]

D. Li and R. B. Kaner, “Graphene-based materials,” Science 320, 1170–1171 (2008).
[CrossRef]

B. Das, R. Voggu, C. S. Rout, and C. N. R. Rao, “Changes in the electronic structure and properties of graphene induced by molecular charge-transfer,” Chem. Commun. 44, 5155–5157 (2008).
[CrossRef]

F. Rana, “Graphene terahertz plasmon oscillators,” IEEE Trans. Nanotechnol. 7, 91–99 (2008).
[CrossRef]

R. R. Nair, P. Blake, A. N. Grigorenko, K. S. Novoselov, T. J. Booth, T. Stauber, N. M. R. Peres, and A. K. Geim, “Fine structure constant defines visual transparency of graphene,” Science 320, 1308 (2008).
[CrossRef]

J. M. Dawlaty, S. Shivaraman, M. Chandrashekhar, F. Rana, and M. G. Spencer, “Measurement of ultrafast carrier dynamics in epitaxial graphene,” Appl. Phys. Lett. 92, 042116 (2008).
[CrossRef]

2007

C. Wang, Y. Fu, Z. Zhou, Y. Cheng, and Z. Xu, “Femtosecond filamentation and supercontinuum generation in silver-nanoparticle-doped water,” Appl. Phys. Lett. 90, 181119 (2007).
[CrossRef]

J. R. Williams, L. DiCarlo, and C. M. Marcus, “Quantum hall effect in a gate-controlled p-n junction of graphene,” Science 317, 638–641 (2007).
[CrossRef]

2006

J. Lakowicz, “Plasmonics in biology and plasmon-controlled fluorescence,” Plasmonics 1, 5–33 (2006).
[CrossRef]

G. G. Wildgoose, C. E. Banks, and R. G. Compton, “Metal nanoparticles and related materials supported on carbon nanotubes: methods and applications,” Small 2, 182–193 (2006).
[CrossRef]

2005

Y. Gao, X. Zhang, Y. Li, H. Liu, Y. Wang, Q. Chang, W. Jiao, and Y. Song, “Saturable absorption and reverse saturable absorption in platinum nanoparticles,” Opt. Commun. 251, 429–433 (2005).
[CrossRef]

J. He, Y. Qu, H. Li, J. Mi, and W. Ji, “Three-photon absorption in ZnO and ZnS crystals,” Opt. Express 13, 9235–9247 (2005).
[CrossRef]

2004

K. S. Novoselov, A. K. Geim, S. V. Morozov, D. Jiang, Y. Zhang, S. V. Dubonos, I. V. Grigorieva, and A. A. Firsov, “Electric field effect in atomically thin carbon films,” Science 306, 666–669 (2004).
[CrossRef]

2003

2002

2001

R. A. Ganeev and et al., “Nonlinear susceptibilities, absorption coefficients and refractive indices of colloidal metals,” J. Phys. D 34, 1602–1611 (2001).
[CrossRef]

2000

1998

P. V. Kamat, M. Flumiani, and G. V. Hartland, “Picosecond dynamics of silver nanoclusters. Photoejection of electrons and fragmentation,” J. Phys. Chem. B 102, 3123–3128 (1998).
[CrossRef]

1996

P. Mulvaney, “Surface plasmon spectroscopy of nanosized metal particles,” Langmuir 12, 788–800 (1996).
[CrossRef]

T.-H. Wei and T.-H. Huang, “A study of photophysics using the Z-scan technique: lifetime determination for high-lying excited states,” Opt. Quantum Electron. 28, 1495–1508 (1996).
[CrossRef]

A. P. Alivisatos, “Semiconductor clusters, nanocrystals, and quantum dots,” Science 271, 933–937 (1996).
[CrossRef]

1990

M. Sheik-Bahae, A. A. Said, T. H. Wei, D. J. Hagan, and E. W. Van Stryland, “Sensitive measurement of optical nonlinearities using a single beam,” IEEE J. Quantum Electron. 26, 760–769 (1990).
[CrossRef]

1979

J. A. Creighton, C. G. Blatchford, and M. G. Albrecht, “Plasma resonance enhancement of Raman scattering by pyridine adsorbed on silver or gold sol particles of size comparable to the excitation wavelength,” J. Chem. Soc. Faraday Trans. 2 75, 790–798 (1979).
[CrossRef]

1958

W. S. Hummers and R. E. Offeman, “Preparation of graphitic oxide,” J. Am. Chem. Soc. 80, 1339–1339 (1958).
[CrossRef]

Albrecht, M. G.

J. A. Creighton, C. G. Blatchford, and M. G. Albrecht, “Plasma resonance enhancement of Raman scattering by pyridine adsorbed on silver or gold sol particles of size comparable to the excitation wavelength,” J. Chem. Soc. Faraday Trans. 2 75, 790–798 (1979).
[CrossRef]

Alivisatos, A. P.

A. P. Alivisatos, “Semiconductor clusters, nanocrystals, and quantum dots,” Science 271, 933–937 (1996).
[CrossRef]

Anija, M.

S. Kumar, M. Anija, N. Kamaraju, K. S. Vasu, K. S. Subrahmanyam, A. K. Sood, and C. N. R. Rao, “Femtosecond carrier dynamics and saturable absorption in graphene suspensions,” Appl. Phys. Lett. 95, 191911 (2009).
[CrossRef]

Baby, T. T.

T. T. Baby and S. Ramaprabhu, “Synthesis and nanofluid application of silver nanoparticles decorated graphene,” J. Mater. Chem. 21, 9702–9709 (2011).
[CrossRef]

A. Kaniyoor, T. T. Baby, and S. Ramaprabhu, “Graphene synthesis via hydrogen induced low temperature exfoliation of graphite oxide,” J. Mater. Chem. 20, 8467–8469 (2010).
[CrossRef]

Banks, C. E.

G. G. Wildgoose, C. E. Banks, and R. G. Compton, “Metal nanoparticles and related materials supported on carbon nanotubes: methods and applications,” Small 2, 182–193 (2006).
[CrossRef]

Barbarin, Y.

Basko, D. M.

Z. Sun, T. Hasan, F. Torrisi, D. Popa, G. Privitera, F. Wang, F. Bonaccorso, D. M. Basko, and A. C. Ferrari, “Graphene mode-locked ultrafast laser,” ACS Nano 4, 803–810 (2010).
[CrossRef]

Bellancourt, A. R.

Bisht, P. B.

B. S. Kalanoor and P. B. Bisht, “Wavelength dependent resonant nonlinearities in a standard saturable absorber IR26 on picosecond time scale,” Opt. Commun. 283, 4059–4063 (2010).
[CrossRef]

Blake, P.

R. R. Nair, P. Blake, A. N. Grigorenko, K. S. Novoselov, T. J. Booth, T. Stauber, N. M. R. Peres, and A. K. Geim, “Fine structure constant defines visual transparency of graphene,” Science 320, 1308 (2008).
[CrossRef]

Blatchford, C. G.

J. A. Creighton, C. G. Blatchford, and M. G. Albrecht, “Plasma resonance enhancement of Raman scattering by pyridine adsorbed on silver or gold sol particles of size comparable to the excitation wavelength,” J. Chem. Soc. Faraday Trans. 2 75, 790–798 (1979).
[CrossRef]

Blau, W. J.

J. Wang, Y. Hernandez, M. Lotya, J. N. Coleman, and W. J. Blau, “Broadband nonlinear optical response of graphene dispersions,” Adv. Mater. 21, 2430–2435 (2009).
[CrossRef]

Bonaccorso, F.

F. Bonaccorso, Z. Sun, T. Hasan, and A. C. Ferrari, “Graphene photonics and optoelectronics,” Nat. Photon. 4, 611–622 (2010).
[CrossRef]

Z. Sun, T. Hasan, F. Torrisi, D. Popa, G. Privitera, F. Wang, F. Bonaccorso, D. M. Basko, and A. C. Ferrari, “Graphene mode-locked ultrafast laser,” ACS Nano 4, 803–810 (2010).
[CrossRef]

Booth, T. J.

R. R. Nair, P. Blake, A. N. Grigorenko, K. S. Novoselov, T. J. Booth, T. Stauber, N. M. R. Peres, and A. K. Geim, “Fine structure constant defines visual transparency of graphene,” Science 320, 1308 (2008).
[CrossRef]

Brooks, E.

U. Gurudas, E. Brooks, D. M. Bubb, S. Heiroth, T. Lippert, and A. Wokaun, “Saturable and reverse saturable absorption in silver nanodots at 532 nm using picosecond laser pulses,” J. Appl. Phys. 104, 073107 (2008).
[CrossRef]

Bubb, D. M.

U. Gurudas, E. Brooks, D. M. Bubb, S. Heiroth, T. Lippert, and A. Wokaun, “Saturable and reverse saturable absorption in silver nanodots at 532 nm using picosecond laser pulses,” J. Appl. Phys. 104, 073107 (2008).
[CrossRef]

Chakraborty, B.

A. Das, S. Pisana, B. Chakraborty, S. Piscanec, S. K. Saha, U. V. Waghmare, K. S. Novoselov, H. R. Krishnamurthy, A. K. Geim, A. C. Ferrari, and A. K. Sood, “Monitoring dopants by Raman scattering in an electrochemically top-gated graphene transistor,” Nat. Nanotechnol. 3, 210–215 (2008).
[CrossRef]

Chandrashekhar, M.

J. M. Dawlaty, S. Shivaraman, M. Chandrashekhar, F. Rana, and M. G. Spencer, “Measurement of ultrafast carrier dynamics in epitaxial graphene,” Appl. Phys. Lett. 92, 042116 (2008).
[CrossRef]

Chang, Q.

Y. Gao, X. Zhang, Y. Li, H. Liu, Y. Wang, Q. Chang, W. Jiao, and Y. Song, “Saturable absorption and reverse saturable absorption in platinum nanoparticles,” Opt. Commun. 251, 429–433 (2005).
[CrossRef]

Chen, P.

Chen, Y.

Z. Liu, Y. Wang, X. Zhang, Y. Xu, Y. Chen, and J. Tian, “Nonlinear optical properties of graphene oxide in nanosecond and picosecond regimes,” Appl. Phys. Lett. 94, 021902 (2009).
[CrossRef]

Cheng, Y.

C. Wang, Y. Fu, Z. Zhou, Y. Cheng, and Z. Xu, “Femtosecond filamentation and supercontinuum generation in silver-nanoparticle-doped water,” Appl. Phys. Lett. 90, 181119 (2007).
[CrossRef]

Chin, S. L.

Coleman, J. N.

J. Wang, Y. Hernandez, M. Lotya, J. N. Coleman, and W. J. Blau, “Broadband nonlinear optical response of graphene dispersions,” Adv. Mater. 21, 2430–2435 (2009).
[CrossRef]

Compton, R. G.

G. G. Wildgoose, C. E. Banks, and R. G. Compton, “Metal nanoparticles and related materials supported on carbon nanotubes: methods and applications,” Small 2, 182–193 (2006).
[CrossRef]

Creighton, J. A.

J. A. Creighton, C. G. Blatchford, and M. G. Albrecht, “Plasma resonance enhancement of Raman scattering by pyridine adsorbed on silver or gold sol particles of size comparable to the excitation wavelength,” J. Chem. Soc. Faraday Trans. 2 75, 790–798 (1979).
[CrossRef]

Das, A.

A. Das, S. Pisana, B. Chakraborty, S. Piscanec, S. K. Saha, U. V. Waghmare, K. S. Novoselov, H. R. Krishnamurthy, A. K. Geim, A. C. Ferrari, and A. K. Sood, “Monitoring dopants by Raman scattering in an electrochemically top-gated graphene transistor,” Nat. Nanotechnol. 3, 210–215 (2008).
[CrossRef]

Das, B.

B. Das, R. Voggu, C. S. Rout, and C. N. R. Rao, “Changes in the electronic structure and properties of graphene induced by molecular charge-transfer,” Chem. Commun. 44, 5155–5157 (2008).
[CrossRef]

Dawlaty, J. M.

J. M. Dawlaty, S. Shivaraman, M. Chandrashekhar, F. Rana, and M. G. Spencer, “Measurement of ultrafast carrier dynamics in epitaxial graphene,” Appl. Phys. Lett. 92, 042116 (2008).
[CrossRef]

DiCarlo, L.

J. R. Williams, L. DiCarlo, and C. M. Marcus, “Quantum hall effect in a gate-controlled p-n junction of graphene,” Science 317, 638–641 (2007).
[CrossRef]

Dubonos, S. V.

K. S. Novoselov, A. K. Geim, S. V. Morozov, D. Jiang, Y. Zhang, S. V. Dubonos, I. V. Grigorieva, and A. A. Firsov, “Electric field effect in atomically thin carbon films,” Science 306, 666–669 (2004).
[CrossRef]

Ferrari, A. C.

F. Bonaccorso, Z. Sun, T. Hasan, and A. C. Ferrari, “Graphene photonics and optoelectronics,” Nat. Photon. 4, 611–622 (2010).
[CrossRef]

Z. Sun, T. Hasan, F. Torrisi, D. Popa, G. Privitera, F. Wang, F. Bonaccorso, D. M. Basko, and A. C. Ferrari, “Graphene mode-locked ultrafast laser,” ACS Nano 4, 803–810 (2010).
[CrossRef]

A. Das, S. Pisana, B. Chakraborty, S. Piscanec, S. K. Saha, U. V. Waghmare, K. S. Novoselov, H. R. Krishnamurthy, A. K. Geim, A. C. Ferrari, and A. K. Sood, “Monitoring dopants by Raman scattering in an electrochemically top-gated graphene transistor,” Nat. Nanotechnol. 3, 210–215 (2008).
[CrossRef]

Firsov, A. A.

K. S. Novoselov, A. K. Geim, S. V. Morozov, D. Jiang, Y. Zhang, S. V. Dubonos, I. V. Grigorieva, and A. A. Firsov, “Electric field effect in atomically thin carbon films,” Science 306, 666–669 (2004).
[CrossRef]

Flumiani, M.

P. V. Kamat, M. Flumiani, and G. V. Hartland, “Picosecond dynamics of silver nanoclusters. Photoejection of electrons and fragmentation,” J. Phys. Chem. B 102, 3123–3128 (1998).
[CrossRef]

Fu, Y.

C. Wang, Y. Fu, Z. Zhou, Y. Cheng, and Z. Xu, “Femtosecond filamentation and supercontinuum generation in silver-nanoparticle-doped water,” Appl. Phys. Lett. 90, 181119 (2007).
[CrossRef]

Ganeev, R. A.

R. A. Ganeev and et al., “Nonlinear susceptibilities, absorption coefficients and refractive indices of colloidal metals,” J. Phys. D 34, 1602–1611 (2001).
[CrossRef]

Gao, Y.

Y. Gao, X. Zhang, Y. Li, H. Liu, Y. Wang, Q. Chang, W. Jiao, and Y. Song, “Saturable absorption and reverse saturable absorption in platinum nanoparticles,” Opt. Commun. 251, 429–433 (2005).
[CrossRef]

Geim, A. K.

A. Das, S. Pisana, B. Chakraborty, S. Piscanec, S. K. Saha, U. V. Waghmare, K. S. Novoselov, H. R. Krishnamurthy, A. K. Geim, A. C. Ferrari, and A. K. Sood, “Monitoring dopants by Raman scattering in an electrochemically top-gated graphene transistor,” Nat. Nanotechnol. 3, 210–215 (2008).
[CrossRef]

R. R. Nair, P. Blake, A. N. Grigorenko, K. S. Novoselov, T. J. Booth, T. Stauber, N. M. R. Peres, and A. K. Geim, “Fine structure constant defines visual transparency of graphene,” Science 320, 1308 (2008).
[CrossRef]

K. S. Novoselov, A. K. Geim, S. V. Morozov, D. Jiang, Y. Zhang, S. V. Dubonos, I. V. Grigorieva, and A. A. Firsov, “Electric field effect in atomically thin carbon films,” Science 306, 666–669 (2004).
[CrossRef]

Golling, M.

Goncalves, G.

G. Goncalves, P. A. A. P. Marques, C. M. Granadeiro, H. I. S. Nogueira, M. K. Singh, and J. Grácio, “Surface modification of graphene nanosheets with gold nanoparticles: the role of oxygen moieties at graphene surface on gold nucleation and growth,” Chem. Mater. 21, 4796–4802 (2009).
[CrossRef]

Grácio, J.

G. Goncalves, P. A. A. P. Marques, C. M. Granadeiro, H. I. S. Nogueira, M. K. Singh, and J. Grácio, “Surface modification of graphene nanosheets with gold nanoparticles: the role of oxygen moieties at graphene surface on gold nucleation and growth,” Chem. Mater. 21, 4796–4802 (2009).
[CrossRef]

Granadeiro, C. M.

G. Goncalves, P. A. A. P. Marques, C. M. Granadeiro, H. I. S. Nogueira, M. K. Singh, and J. Grácio, “Surface modification of graphene nanosheets with gold nanoparticles: the role of oxygen moieties at graphene surface on gold nucleation and growth,” Chem. Mater. 21, 4796–4802 (2009).
[CrossRef]

Grigorenko, A. N.

R. R. Nair, P. Blake, A. N. Grigorenko, K. S. Novoselov, T. J. Booth, T. Stauber, N. M. R. Peres, and A. K. Geim, “Fine structure constant defines visual transparency of graphene,” Science 320, 1308 (2008).
[CrossRef]

Grigorieva, I. V.

K. S. Novoselov, A. K. Geim, S. V. Morozov, D. Jiang, Y. Zhang, S. V. Dubonos, I. V. Grigorieva, and A. A. Firsov, “Electric field effect in atomically thin carbon films,” Science 306, 666–669 (2004).
[CrossRef]

Guo, M.

Z. Zhang, F. Xu, W. Yang, M. Guo, X. Wang, B. Zhang, and J. Tang, “A facile one-pot method to high-quality Ag-graphene composite nanosheets for efficient surface-enhanced Raman scattering,” Chem. Commun. 47, 6440–6442 (2011).
[CrossRef]

Gurudas, U.

U. Gurudas, E. Brooks, D. M. Bubb, S. Heiroth, T. Lippert, and A. Wokaun, “Saturable and reverse saturable absorption in silver nanodots at 532 nm using picosecond laser pulses,” J. Appl. Phys. 104, 073107 (2008).
[CrossRef]

Hagan, D. J.

X. Sun, Y. Xiong, P. Chen, J. Lin, W. Ji, J. H. Lim, S. S. Yang, D. J. Hagan, and E. W. Van Stryland, “Investigation of an optical limiting mechanism in multiwalled carbon nanotubes,” Appl. Opt. 39, 1998–2001 (2000).
[CrossRef]

M. Sheik-Bahae, A. A. Said, T. H. Wei, D. J. Hagan, and E. W. Van Stryland, “Sensitive measurement of optical nonlinearities using a single beam,” IEEE J. Quantum Electron. 26, 760–769 (1990).
[CrossRef]

Hartland, G. V.

P. V. Kamat, M. Flumiani, and G. V. Hartland, “Picosecond dynamics of silver nanoclusters. Photoejection of electrons and fragmentation,” J. Phys. Chem. B 102, 3123–3128 (1998).
[CrossRef]

Hasan, T.

F. Bonaccorso, Z. Sun, T. Hasan, and A. C. Ferrari, “Graphene photonics and optoelectronics,” Nat. Photon. 4, 611–622 (2010).
[CrossRef]

Z. Sun, T. Hasan, F. Torrisi, D. Popa, G. Privitera, F. Wang, F. Bonaccorso, D. M. Basko, and A. C. Ferrari, “Graphene mode-locked ultrafast laser,” ACS Nano 4, 803–810 (2010).
[CrossRef]

He, J.

Heiroth, S.

U. Gurudas, E. Brooks, D. M. Bubb, S. Heiroth, T. Lippert, and A. Wokaun, “Saturable and reverse saturable absorption in silver nanodots at 532 nm using picosecond laser pulses,” J. Appl. Phys. 104, 073107 (2008).
[CrossRef]

Hernandez, Y.

J. Wang, Y. Hernandez, M. Lotya, J. N. Coleman, and W. J. Blau, “Broadband nonlinear optical response of graphene dispersions,” Adv. Mater. 21, 2430–2435 (2009).
[CrossRef]

Hoffmann, M.

Huang, T.-H.

T.-H. Wei and T.-H. Huang, “A study of photophysics using the Z-scan technique: lifetime determination for high-lying excited states,” Opt. Quantum Electron. 28, 1495–1508 (1996).
[CrossRef]

Hummers, W. S.

W. S. Hummers and R. E. Offeman, “Preparation of graphitic oxide,” J. Am. Chem. Soc. 80, 1339–1339 (1958).
[CrossRef]

Ji, W.

Jiang, D.

K. S. Novoselov, A. K. Geim, S. V. Morozov, D. Jiang, Y. Zhang, S. V. Dubonos, I. V. Grigorieva, and A. A. Firsov, “Electric field effect in atomically thin carbon films,” Science 306, 666–669 (2004).
[CrossRef]

Jiao, W.

Y. Gao, X. Zhang, Y. Li, H. Liu, Y. Wang, Q. Chang, W. Jiao, and Y. Song, “Saturable absorption and reverse saturable absorption in platinum nanoparticles,” Opt. Commun. 251, 429–433 (2005).
[CrossRef]

Kalanoor, B. S.

B. S. Kalanoor and P. B. Bisht, “Wavelength dependent resonant nonlinearities in a standard saturable absorber IR26 on picosecond time scale,” Opt. Commun. 283, 4059–4063 (2010).
[CrossRef]

Kamaraju, N.

S. Kumar, M. Anija, N. Kamaraju, K. S. Vasu, K. S. Subrahmanyam, A. K. Sood, and C. N. R. Rao, “Femtosecond carrier dynamics and saturable absorption in graphene suspensions,” Appl. Phys. Lett. 95, 191911 (2009).
[CrossRef]

Kamat, P. V.

P. V. Kamat, M. Flumiani, and G. V. Hartland, “Picosecond dynamics of silver nanoclusters. Photoejection of electrons and fragmentation,” J. Phys. Chem. B 102, 3123–3128 (1998).
[CrossRef]

Kaner, R. B.

D. Li and R. B. Kaner, “Graphene-based materials,” Science 320, 1170–1171 (2008).
[CrossRef]

Kaniyoor, A.

A. Kaniyoor, T. T. Baby, and S. Ramaprabhu, “Graphene synthesis via hydrogen induced low temperature exfoliation of graphite oxide,” J. Mater. Chem. 20, 8467–8469 (2010).
[CrossRef]

Keller, U.

Knize, R. J.

W. D. Tan, C. Y. Su, R. J. Knize, G. Q. Xie, L. J. Li, and D. Y. Tang, “Mode locking of ceramic Nd:yttrium aluminum garnet with graphene as a saturable absorber,” Appl. Phys. Lett. 96, 031106 (2010).
[CrossRef]

Krishnamurthy, H. R.

A. Das, S. Pisana, B. Chakraborty, S. Piscanec, S. K. Saha, U. V. Waghmare, K. S. Novoselov, H. R. Krishnamurthy, A. K. Geim, A. C. Ferrari, and A. K. Sood, “Monitoring dopants by Raman scattering in an electrochemically top-gated graphene transistor,” Nat. Nanotechnol. 3, 210–215 (2008).
[CrossRef]

Kumar, S.

S. Kumar, M. Anija, N. Kamaraju, K. S. Vasu, K. S. Subrahmanyam, A. K. Sood, and C. N. R. Rao, “Femtosecond carrier dynamics and saturable absorption in graphene suspensions,” Appl. Phys. Lett. 95, 191911 (2009).
[CrossRef]

Lakowicz, J.

J. Lakowicz, “Plasmonics in biology and plasmon-controlled fluorescence,” Plasmonics 1, 5–33 (2006).
[CrossRef]

Li, D.

D. Li and R. B. Kaner, “Graphene-based materials,” Science 320, 1170–1171 (2008).
[CrossRef]

Li, H.

Li, L. J.

W. D. Tan, C. Y. Su, R. J. Knize, G. Q. Xie, L. J. Li, and D. Y. Tang, “Mode locking of ceramic Nd:yttrium aluminum garnet with graphene as a saturable absorber,” Appl. Phys. Lett. 96, 031106 (2010).
[CrossRef]

Li, Y.

Y. Gao, X. Zhang, Y. Li, H. Liu, Y. Wang, Q. Chang, W. Jiao, and Y. Song, “Saturable absorption and reverse saturable absorption in platinum nanoparticles,” Opt. Commun. 251, 429–433 (2005).
[CrossRef]

Lim, J. H.

Lin, J.

Lippert, T.

U. Gurudas, E. Brooks, D. M. Bubb, S. Heiroth, T. Lippert, and A. Wokaun, “Saturable and reverse saturable absorption in silver nanodots at 532 nm using picosecond laser pulses,” J. Appl. Phys. 104, 073107 (2008).
[CrossRef]

Liu, H.

Y. Gao, X. Zhang, Y. Li, H. Liu, Y. Wang, Q. Chang, W. Jiao, and Y. Song, “Saturable absorption and reverse saturable absorption in platinum nanoparticles,” Opt. Commun. 251, 429–433 (2005).
[CrossRef]

Liu, Z.

Z. Liu, Y. Wang, X. Zhang, Y. Xu, Y. Chen, and J. Tian, “Nonlinear optical properties of graphene oxide in nanosecond and picosecond regimes,” Appl. Phys. Lett. 94, 021902 (2009).
[CrossRef]

Lotya, M.

J. Wang, Y. Hernandez, M. Lotya, J. N. Coleman, and W. J. Blau, “Broadband nonlinear optical response of graphene dispersions,” Adv. Mater. 21, 2430–2435 (2009).
[CrossRef]

Maas, D. J. H. C.

Manna, A. K.

K. S. Subrahmanyam, A. K. Manna, S. K. Pati, and C. N. R. Rao, “A study of graphene decorated with metal nanoparticles,” Chem. Phys. Lett. 497, 70–75 (2010).
[CrossRef]

Marcus, C. M.

J. R. Williams, L. DiCarlo, and C. M. Marcus, “Quantum hall effect in a gate-controlled p-n junction of graphene,” Science 317, 638–641 (2007).
[CrossRef]

Marques, P. A. A. P.

G. Goncalves, P. A. A. P. Marques, C. M. Granadeiro, H. I. S. Nogueira, M. K. Singh, and J. Grácio, “Surface modification of graphene nanosheets with gold nanoparticles: the role of oxygen moieties at graphene surface on gold nucleation and growth,” Chem. Mater. 21, 4796–4802 (2009).
[CrossRef]

Mi, J.

Morozov, S. V.

K. S. Novoselov, A. K. Geim, S. V. Morozov, D. Jiang, Y. Zhang, S. V. Dubonos, I. V. Grigorieva, and A. A. Firsov, “Electric field effect in atomically thin carbon films,” Science 306, 666–669 (2004).
[CrossRef]

Moses, E.

Mulvaney, P.

P. Mulvaney, “Surface plasmon spectroscopy of nanosized metal particles,” Langmuir 12, 788–800 (1996).
[CrossRef]

Nair, R. R.

R. R. Nair, P. Blake, A. N. Grigorenko, K. S. Novoselov, T. J. Booth, T. Stauber, N. M. R. Peres, and A. K. Geim, “Fine structure constant defines visual transparency of graphene,” Science 320, 1308 (2008).
[CrossRef]

Nogueira, H. I. S.

G. Goncalves, P. A. A. P. Marques, C. M. Granadeiro, H. I. S. Nogueira, M. K. Singh, and J. Grácio, “Surface modification of graphene nanosheets with gold nanoparticles: the role of oxygen moieties at graphene surface on gold nucleation and growth,” Chem. Mater. 21, 4796–4802 (2009).
[CrossRef]

Novoselov, K. S.

A. Das, S. Pisana, B. Chakraborty, S. Piscanec, S. K. Saha, U. V. Waghmare, K. S. Novoselov, H. R. Krishnamurthy, A. K. Geim, A. C. Ferrari, and A. K. Sood, “Monitoring dopants by Raman scattering in an electrochemically top-gated graphene transistor,” Nat. Nanotechnol. 3, 210–215 (2008).
[CrossRef]

R. R. Nair, P. Blake, A. N. Grigorenko, K. S. Novoselov, T. J. Booth, T. Stauber, N. M. R. Peres, and A. K. Geim, “Fine structure constant defines visual transparency of graphene,” Science 320, 1308 (2008).
[CrossRef]

K. S. Novoselov, A. K. Geim, S. V. Morozov, D. Jiang, Y. Zhang, S. V. Dubonos, I. V. Grigorieva, and A. A. Firsov, “Electric field effect in atomically thin carbon films,” Science 306, 666–669 (2004).
[CrossRef]

Offeman, R. E.

W. S. Hummers and R. E. Offeman, “Preparation of graphitic oxide,” J. Am. Chem. Soc. 80, 1339–1339 (1958).
[CrossRef]

Oron, D.

Pati, S. K.

K. S. Subrahmanyam, A. K. Manna, S. K. Pati, and C. N. R. Rao, “A study of graphene decorated with metal nanoparticles,” Chem. Phys. Lett. 497, 70–75 (2010).
[CrossRef]

Peres, N. M. R.

R. R. Nair, P. Blake, A. N. Grigorenko, K. S. Novoselov, T. J. Booth, T. Stauber, N. M. R. Peres, and A. K. Geim, “Fine structure constant defines visual transparency of graphene,” Science 320, 1308 (2008).
[CrossRef]

Petit, S.

Pisana, S.

A. Das, S. Pisana, B. Chakraborty, S. Piscanec, S. K. Saha, U. V. Waghmare, K. S. Novoselov, H. R. Krishnamurthy, A. K. Geim, A. C. Ferrari, and A. K. Sood, “Monitoring dopants by Raman scattering in an electrochemically top-gated graphene transistor,” Nat. Nanotechnol. 3, 210–215 (2008).
[CrossRef]

Piscanec, S.

A. Das, S. Pisana, B. Chakraborty, S. Piscanec, S. K. Saha, U. V. Waghmare, K. S. Novoselov, H. R. Krishnamurthy, A. K. Geim, A. C. Ferrari, and A. K. Sood, “Monitoring dopants by Raman scattering in an electrochemically top-gated graphene transistor,” Nat. Nanotechnol. 3, 210–215 (2008).
[CrossRef]

Popa, D.

Z. Sun, T. Hasan, F. Torrisi, D. Popa, G. Privitera, F. Wang, F. Bonaccorso, D. M. Basko, and A. C. Ferrari, “Graphene mode-locked ultrafast laser,” ACS Nano 4, 803–810 (2010).
[CrossRef]

Privitera, G.

Z. Sun, T. Hasan, F. Torrisi, D. Popa, G. Privitera, F. Wang, F. Bonaccorso, D. M. Basko, and A. C. Ferrari, “Graphene mode-locked ultrafast laser,” ACS Nano 4, 803–810 (2010).
[CrossRef]

Qu, Y.

Ramaprabhu, S.

T. T. Baby and S. Ramaprabhu, “Synthesis and nanofluid application of silver nanoparticles decorated graphene,” J. Mater. Chem. 21, 9702–9709 (2011).
[CrossRef]

A. Kaniyoor, T. T. Baby, and S. Ramaprabhu, “Graphene synthesis via hydrogen induced low temperature exfoliation of graphite oxide,” J. Mater. Chem. 20, 8467–8469 (2010).
[CrossRef]

Rana, F.

J. M. Dawlaty, S. Shivaraman, M. Chandrashekhar, F. Rana, and M. G. Spencer, “Measurement of ultrafast carrier dynamics in epitaxial graphene,” Appl. Phys. Lett. 92, 042116 (2008).
[CrossRef]

F. Rana, “Graphene terahertz plasmon oscillators,” IEEE Trans. Nanotechnol. 7, 91–99 (2008).
[CrossRef]

Rao, C. N. R.

K. S. Subrahmanyam, A. K. Manna, S. K. Pati, and C. N. R. Rao, “A study of graphene decorated with metal nanoparticles,” Chem. Phys. Lett. 497, 70–75 (2010).
[CrossRef]

S. Kumar, M. Anija, N. Kamaraju, K. S. Vasu, K. S. Subrahmanyam, A. K. Sood, and C. N. R. Rao, “Femtosecond carrier dynamics and saturable absorption in graphene suspensions,” Appl. Phys. Lett. 95, 191911 (2009).
[CrossRef]

B. Das, R. Voggu, C. S. Rout, and C. N. R. Rao, “Changes in the electronic structure and properties of graphene induced by molecular charge-transfer,” Chem. Commun. 44, 5155–5157 (2008).
[CrossRef]

Rout, C. S.

B. Das, R. Voggu, C. S. Rout, and C. N. R. Rao, “Changes in the electronic structure and properties of graphene induced by molecular charge-transfer,” Chem. Commun. 44, 5155–5157 (2008).
[CrossRef]

Rudin, B.

Saha, S. K.

A. Das, S. Pisana, B. Chakraborty, S. Piscanec, S. K. Saha, U. V. Waghmare, K. S. Novoselov, H. R. Krishnamurthy, A. K. Geim, A. C. Ferrari, and A. K. Sood, “Monitoring dopants by Raman scattering in an electrochemically top-gated graphene transistor,” Nat. Nanotechnol. 3, 210–215 (2008).
[CrossRef]

Said, A. A.

M. Sheik-Bahae, A. A. Said, T. H. Wei, D. J. Hagan, and E. W. Van Stryland, “Sensitive measurement of optical nonlinearities using a single beam,” IEEE J. Quantum Electron. 26, 760–769 (1990).
[CrossRef]

Sheik-Bahae, M.

M. Sheik-Bahae, A. A. Said, T. H. Wei, D. J. Hagan, and E. W. Van Stryland, “Sensitive measurement of optical nonlinearities using a single beam,” IEEE J. Quantum Electron. 26, 760–769 (1990).
[CrossRef]

Shivaraman, S.

J. M. Dawlaty, S. Shivaraman, M. Chandrashekhar, F. Rana, and M. G. Spencer, “Measurement of ultrafast carrier dynamics in epitaxial graphene,” Appl. Phys. Lett. 92, 042116 (2008).
[CrossRef]

Siegman, A. E.

A. E. Siegman, Lasers (University Science, 1986).

Silberberg, Y.

Singh, M. K.

G. Goncalves, P. A. A. P. Marques, C. M. Granadeiro, H. I. S. Nogueira, M. K. Singh, and J. Grácio, “Surface modification of graphene nanosheets with gold nanoparticles: the role of oxygen moieties at graphene surface on gold nucleation and growth,” Chem. Mater. 21, 4796–4802 (2009).
[CrossRef]

Song, Y.

Y. Gao, X. Zhang, Y. Li, H. Liu, Y. Wang, Q. Chang, W. Jiao, and Y. Song, “Saturable absorption and reverse saturable absorption in platinum nanoparticles,” Opt. Commun. 251, 429–433 (2005).
[CrossRef]

Sood, A. K.

S. Kumar, M. Anija, N. Kamaraju, K. S. Vasu, K. S. Subrahmanyam, A. K. Sood, and C. N. R. Rao, “Femtosecond carrier dynamics and saturable absorption in graphene suspensions,” Appl. Phys. Lett. 95, 191911 (2009).
[CrossRef]

A. Das, S. Pisana, B. Chakraborty, S. Piscanec, S. K. Saha, U. V. Waghmare, K. S. Novoselov, H. R. Krishnamurthy, A. K. Geim, A. C. Ferrari, and A. K. Sood, “Monitoring dopants by Raman scattering in an electrochemically top-gated graphene transistor,” Nat. Nanotechnol. 3, 210–215 (2008).
[CrossRef]

Spencer, M. G.

J. M. Dawlaty, S. Shivaraman, M. Chandrashekhar, F. Rana, and M. G. Spencer, “Measurement of ultrafast carrier dynamics in epitaxial graphene,” Appl. Phys. Lett. 92, 042116 (2008).
[CrossRef]

Stauber, T.

R. R. Nair, P. Blake, A. N. Grigorenko, K. S. Novoselov, T. J. Booth, T. Stauber, N. M. R. Peres, and A. K. Geim, “Fine structure constant defines visual transparency of graphene,” Science 320, 1308 (2008).
[CrossRef]

Su, C. Y.

W. D. Tan, C. Y. Su, R. J. Knize, G. Q. Xie, L. J. Li, and D. Y. Tang, “Mode locking of ceramic Nd:yttrium aluminum garnet with graphene as a saturable absorber,” Appl. Phys. Lett. 96, 031106 (2010).
[CrossRef]

Subrahmanyam, K. S.

K. S. Subrahmanyam, A. K. Manna, S. K. Pati, and C. N. R. Rao, “A study of graphene decorated with metal nanoparticles,” Chem. Phys. Lett. 497, 70–75 (2010).
[CrossRef]

S. Kumar, M. Anija, N. Kamaraju, K. S. Vasu, K. S. Subrahmanyam, A. K. Sood, and C. N. R. Rao, “Femtosecond carrier dynamics and saturable absorption in graphene suspensions,” Appl. Phys. Lett. 95, 191911 (2009).
[CrossRef]

Südmeyer, T.

Sun, X.

Sun, Z.

F. Bonaccorso, Z. Sun, T. Hasan, and A. C. Ferrari, “Graphene photonics and optoelectronics,” Nat. Photon. 4, 611–622 (2010).
[CrossRef]

Z. Sun, T. Hasan, F. Torrisi, D. Popa, G. Privitera, F. Wang, F. Bonaccorso, D. M. Basko, and A. C. Ferrari, “Graphene mode-locked ultrafast laser,” ACS Nano 4, 803–810 (2010).
[CrossRef]

Tan, W. D.

W. D. Tan, C. Y. Su, R. J. Knize, G. Q. Xie, L. J. Li, and D. Y. Tang, “Mode locking of ceramic Nd:yttrium aluminum garnet with graphene as a saturable absorber,” Appl. Phys. Lett. 96, 031106 (2010).
[CrossRef]

Tang, D. Y.

W. D. Tan, C. Y. Su, R. J. Knize, G. Q. Xie, L. J. Li, and D. Y. Tang, “Mode locking of ceramic Nd:yttrium aluminum garnet with graphene as a saturable absorber,” Appl. Phys. Lett. 96, 031106 (2010).
[CrossRef]

Tang, J.

Z. Zhang, F. Xu, W. Yang, M. Guo, X. Wang, B. Zhang, and J. Tang, “A facile one-pot method to high-quality Ag-graphene composite nanosheets for efficient surface-enhanced Raman scattering,” Chem. Commun. 47, 6440–6442 (2011).
[CrossRef]

Thiberge, S.

Tian, J.

Z. Liu, Y. Wang, X. Zhang, Y. Xu, Y. Chen, and J. Tian, “Nonlinear optical properties of graphene oxide in nanosecond and picosecond regimes,” Appl. Phys. Lett. 94, 021902 (2009).
[CrossRef]

Torrisi, F.

Z. Sun, T. Hasan, F. Torrisi, D. Popa, G. Privitera, F. Wang, F. Bonaccorso, D. M. Basko, and A. C. Ferrari, “Graphene mode-locked ultrafast laser,” ACS Nano 4, 803–810 (2010).
[CrossRef]

Van Stryland, E. W.

X. Sun, Y. Xiong, P. Chen, J. Lin, W. Ji, J. H. Lim, S. S. Yang, D. J. Hagan, and E. W. Van Stryland, “Investigation of an optical limiting mechanism in multiwalled carbon nanotubes,” Appl. Opt. 39, 1998–2001 (2000).
[CrossRef]

M. Sheik-Bahae, A. A. Said, T. H. Wei, D. J. Hagan, and E. W. Van Stryland, “Sensitive measurement of optical nonlinearities using a single beam,” IEEE J. Quantum Electron. 26, 760–769 (1990).
[CrossRef]

Vasu, K. S.

S. Kumar, M. Anija, N. Kamaraju, K. S. Vasu, K. S. Subrahmanyam, A. K. Sood, and C. N. R. Rao, “Femtosecond carrier dynamics and saturable absorption in graphene suspensions,” Appl. Phys. Lett. 95, 191911 (2009).
[CrossRef]

Vincent, D.

Voggu, R.

B. Das, R. Voggu, C. S. Rout, and C. N. R. Rao, “Changes in the electronic structure and properties of graphene induced by molecular charge-transfer,” Chem. Commun. 44, 5155–5157 (2008).
[CrossRef]

Waghmare, U. V.

A. Das, S. Pisana, B. Chakraborty, S. Piscanec, S. K. Saha, U. V. Waghmare, K. S. Novoselov, H. R. Krishnamurthy, A. K. Geim, A. C. Ferrari, and A. K. Sood, “Monitoring dopants by Raman scattering in an electrochemically top-gated graphene transistor,” Nat. Nanotechnol. 3, 210–215 (2008).
[CrossRef]

Wang, C.

C. Wang, Y. Fu, Z. Zhou, Y. Cheng, and Z. Xu, “Femtosecond filamentation and supercontinuum generation in silver-nanoparticle-doped water,” Appl. Phys. Lett. 90, 181119 (2007).
[CrossRef]

Wang, F.

Z. Sun, T. Hasan, F. Torrisi, D. Popa, G. Privitera, F. Wang, F. Bonaccorso, D. M. Basko, and A. C. Ferrari, “Graphene mode-locked ultrafast laser,” ACS Nano 4, 803–810 (2010).
[CrossRef]

Wang, J.

J. Wang, Y. Hernandez, M. Lotya, J. N. Coleman, and W. J. Blau, “Broadband nonlinear optical response of graphene dispersions,” Adv. Mater. 21, 2430–2435 (2009).
[CrossRef]

Wang, X.

Z. Zhang, F. Xu, W. Yang, M. Guo, X. Wang, B. Zhang, and J. Tang, “A facile one-pot method to high-quality Ag-graphene composite nanosheets for efficient surface-enhanced Raman scattering,” Chem. Commun. 47, 6440–6442 (2011).
[CrossRef]

Wang, Y.

Z. Liu, Y. Wang, X. Zhang, Y. Xu, Y. Chen, and J. Tian, “Nonlinear optical properties of graphene oxide in nanosecond and picosecond regimes,” Appl. Phys. Lett. 94, 021902 (2009).
[CrossRef]

Y. Gao, X. Zhang, Y. Li, H. Liu, Y. Wang, Q. Chang, W. Jiao, and Y. Song, “Saturable absorption and reverse saturable absorption in platinum nanoparticles,” Opt. Commun. 251, 429–433 (2005).
[CrossRef]

Wei, T. H.

M. Sheik-Bahae, A. A. Said, T. H. Wei, D. J. Hagan, and E. W. Van Stryland, “Sensitive measurement of optical nonlinearities using a single beam,” IEEE J. Quantum Electron. 26, 760–769 (1990).
[CrossRef]

Wei, T.-H.

T.-H. Wei and T.-H. Huang, “A study of photophysics using the Z-scan technique: lifetime determination for high-lying excited states,” Opt. Quantum Electron. 28, 1495–1508 (1996).
[CrossRef]

Wildgoose, G. G.

G. G. Wildgoose, C. E. Banks, and R. G. Compton, “Metal nanoparticles and related materials supported on carbon nanotubes: methods and applications,” Small 2, 182–193 (2006).
[CrossRef]

Williams, J. R.

J. R. Williams, L. DiCarlo, and C. M. Marcus, “Quantum hall effect in a gate-controlled p-n junction of graphene,” Science 317, 638–641 (2007).
[CrossRef]

Wokaun, A.

U. Gurudas, E. Brooks, D. M. Bubb, S. Heiroth, T. Lippert, and A. Wokaun, “Saturable and reverse saturable absorption in silver nanodots at 532 nm using picosecond laser pulses,” J. Appl. Phys. 104, 073107 (2008).
[CrossRef]

Xie, G. Q.

W. D. Tan, C. Y. Su, R. J. Knize, G. Q. Xie, L. J. Li, and D. Y. Tang, “Mode locking of ceramic Nd:yttrium aluminum garnet with graphene as a saturable absorber,” Appl. Phys. Lett. 96, 031106 (2010).
[CrossRef]

Xiong, Y.

Xu, F.

Z. Zhang, F. Xu, W. Yang, M. Guo, X. Wang, B. Zhang, and J. Tang, “A facile one-pot method to high-quality Ag-graphene composite nanosheets for efficient surface-enhanced Raman scattering,” Chem. Commun. 47, 6440–6442 (2011).
[CrossRef]

Xu, Y.

Z. Liu, Y. Wang, X. Zhang, Y. Xu, Y. Chen, and J. Tian, “Nonlinear optical properties of graphene oxide in nanosecond and picosecond regimes,” Appl. Phys. Lett. 94, 021902 (2009).
[CrossRef]

Xu, Z.

C. Wang, Y. Fu, Z. Zhou, Y. Cheng, and Z. Xu, “Femtosecond filamentation and supercontinuum generation in silver-nanoparticle-doped water,” Appl. Phys. Lett. 90, 181119 (2007).
[CrossRef]

Yang, S. S.

Yang, W.

Z. Zhang, F. Xu, W. Yang, M. Guo, X. Wang, B. Zhang, and J. Tang, “A facile one-pot method to high-quality Ag-graphene composite nanosheets for efficient surface-enhanced Raman scattering,” Chem. Commun. 47, 6440–6442 (2011).
[CrossRef]

Yelin, D.

Zhang, B.

Z. Zhang, F. Xu, W. Yang, M. Guo, X. Wang, B. Zhang, and J. Tang, “A facile one-pot method to high-quality Ag-graphene composite nanosheets for efficient surface-enhanced Raman scattering,” Chem. Commun. 47, 6440–6442 (2011).
[CrossRef]

Zhang, X.

Z. Liu, Y. Wang, X. Zhang, Y. Xu, Y. Chen, and J. Tian, “Nonlinear optical properties of graphene oxide in nanosecond and picosecond regimes,” Appl. Phys. Lett. 94, 021902 (2009).
[CrossRef]

Y. Gao, X. Zhang, Y. Li, H. Liu, Y. Wang, Q. Chang, W. Jiao, and Y. Song, “Saturable absorption and reverse saturable absorption in platinum nanoparticles,” Opt. Commun. 251, 429–433 (2005).
[CrossRef]

Zhang, Y.

K. S. Novoselov, A. K. Geim, S. V. Morozov, D. Jiang, Y. Zhang, S. V. Dubonos, I. V. Grigorieva, and A. A. Firsov, “Electric field effect in atomically thin carbon films,” Science 306, 666–669 (2004).
[CrossRef]

Zhang, Z.

Z. Zhang, F. Xu, W. Yang, M. Guo, X. Wang, B. Zhang, and J. Tang, “A facile one-pot method to high-quality Ag-graphene composite nanosheets for efficient surface-enhanced Raman scattering,” Chem. Commun. 47, 6440–6442 (2011).
[CrossRef]

Zhou, Z.

C. Wang, Y. Fu, Z. Zhou, Y. Cheng, and Z. Xu, “Femtosecond filamentation and supercontinuum generation in silver-nanoparticle-doped water,” Appl. Phys. Lett. 90, 181119 (2007).
[CrossRef]

ACS Nano

Z. Sun, T. Hasan, F. Torrisi, D. Popa, G. Privitera, F. Wang, F. Bonaccorso, D. M. Basko, and A. C. Ferrari, “Graphene mode-locked ultrafast laser,” ACS Nano 4, 803–810 (2010).
[CrossRef]

Adv. Mater.

J. Wang, Y. Hernandez, M. Lotya, J. N. Coleman, and W. J. Blau, “Broadband nonlinear optical response of graphene dispersions,” Adv. Mater. 21, 2430–2435 (2009).
[CrossRef]

Appl. Opt.

Appl. Phys. Lett.

Z. Liu, Y. Wang, X. Zhang, Y. Xu, Y. Chen, and J. Tian, “Nonlinear optical properties of graphene oxide in nanosecond and picosecond regimes,” Appl. Phys. Lett. 94, 021902 (2009).
[CrossRef]

S. Kumar, M. Anija, N. Kamaraju, K. S. Vasu, K. S. Subrahmanyam, A. K. Sood, and C. N. R. Rao, “Femtosecond carrier dynamics and saturable absorption in graphene suspensions,” Appl. Phys. Lett. 95, 191911 (2009).
[CrossRef]

W. D. Tan, C. Y. Su, R. J. Knize, G. Q. Xie, L. J. Li, and D. Y. Tang, “Mode locking of ceramic Nd:yttrium aluminum garnet with graphene as a saturable absorber,” Appl. Phys. Lett. 96, 031106 (2010).
[CrossRef]

J. M. Dawlaty, S. Shivaraman, M. Chandrashekhar, F. Rana, and M. G. Spencer, “Measurement of ultrafast carrier dynamics in epitaxial graphene,” Appl. Phys. Lett. 92, 042116 (2008).
[CrossRef]

C. Wang, Y. Fu, Z. Zhou, Y. Cheng, and Z. Xu, “Femtosecond filamentation and supercontinuum generation in silver-nanoparticle-doped water,” Appl. Phys. Lett. 90, 181119 (2007).
[CrossRef]

Chem. Commun.

B. Das, R. Voggu, C. S. Rout, and C. N. R. Rao, “Changes in the electronic structure and properties of graphene induced by molecular charge-transfer,” Chem. Commun. 44, 5155–5157 (2008).
[CrossRef]

Z. Zhang, F. Xu, W. Yang, M. Guo, X. Wang, B. Zhang, and J. Tang, “A facile one-pot method to high-quality Ag-graphene composite nanosheets for efficient surface-enhanced Raman scattering,” Chem. Commun. 47, 6440–6442 (2011).
[CrossRef]

Chem. Mater.

G. Goncalves, P. A. A. P. Marques, C. M. Granadeiro, H. I. S. Nogueira, M. K. Singh, and J. Grácio, “Surface modification of graphene nanosheets with gold nanoparticles: the role of oxygen moieties at graphene surface on gold nucleation and growth,” Chem. Mater. 21, 4796–4802 (2009).
[CrossRef]

Chem. Phys. Lett.

K. S. Subrahmanyam, A. K. Manna, S. K. Pati, and C. N. R. Rao, “A study of graphene decorated with metal nanoparticles,” Chem. Phys. Lett. 497, 70–75 (2010).
[CrossRef]

IEEE J. Quantum Electron.

M. Sheik-Bahae, A. A. Said, T. H. Wei, D. J. Hagan, and E. W. Van Stryland, “Sensitive measurement of optical nonlinearities using a single beam,” IEEE J. Quantum Electron. 26, 760–769 (1990).
[CrossRef]

IEEE Trans. Nanotechnol.

F. Rana, “Graphene terahertz plasmon oscillators,” IEEE Trans. Nanotechnol. 7, 91–99 (2008).
[CrossRef]

J. Am. Chem. Soc.

W. S. Hummers and R. E. Offeman, “Preparation of graphitic oxide,” J. Am. Chem. Soc. 80, 1339–1339 (1958).
[CrossRef]

J. Appl. Phys.

U. Gurudas, E. Brooks, D. M. Bubb, S. Heiroth, T. Lippert, and A. Wokaun, “Saturable and reverse saturable absorption in silver nanodots at 532 nm using picosecond laser pulses,” J. Appl. Phys. 104, 073107 (2008).
[CrossRef]

J. Chem. Soc. Faraday Trans. 2

J. A. Creighton, C. G. Blatchford, and M. G. Albrecht, “Plasma resonance enhancement of Raman scattering by pyridine adsorbed on silver or gold sol particles of size comparable to the excitation wavelength,” J. Chem. Soc. Faraday Trans. 2 75, 790–798 (1979).
[CrossRef]

J. Mater. Chem.

T. T. Baby and S. Ramaprabhu, “Synthesis and nanofluid application of silver nanoparticles decorated graphene,” J. Mater. Chem. 21, 9702–9709 (2011).
[CrossRef]

A. Kaniyoor, T. T. Baby, and S. Ramaprabhu, “Graphene synthesis via hydrogen induced low temperature exfoliation of graphite oxide,” J. Mater. Chem. 20, 8467–8469 (2010).
[CrossRef]

J. Phys. Chem. B

P. V. Kamat, M. Flumiani, and G. V. Hartland, “Picosecond dynamics of silver nanoclusters. Photoejection of electrons and fragmentation,” J. Phys. Chem. B 102, 3123–3128 (1998).
[CrossRef]

J. Phys. D

R. A. Ganeev and et al., “Nonlinear susceptibilities, absorption coefficients and refractive indices of colloidal metals,” J. Phys. D 34, 1602–1611 (2001).
[CrossRef]

Langmuir

P. Mulvaney, “Surface plasmon spectroscopy of nanosized metal particles,” Langmuir 12, 788–800 (1996).
[CrossRef]

Nat. Nanotechnol.

A. Das, S. Pisana, B. Chakraborty, S. Piscanec, S. K. Saha, U. V. Waghmare, K. S. Novoselov, H. R. Krishnamurthy, A. K. Geim, A. C. Ferrari, and A. K. Sood, “Monitoring dopants by Raman scattering in an electrochemically top-gated graphene transistor,” Nat. Nanotechnol. 3, 210–215 (2008).
[CrossRef]

Nat. Photon.

F. Bonaccorso, Z. Sun, T. Hasan, and A. C. Ferrari, “Graphene photonics and optoelectronics,” Nat. Photon. 4, 611–622 (2010).
[CrossRef]

Opt. Commun.

B. S. Kalanoor and P. B. Bisht, “Wavelength dependent resonant nonlinearities in a standard saturable absorber IR26 on picosecond time scale,” Opt. Commun. 283, 4059–4063 (2010).
[CrossRef]

Y. Gao, X. Zhang, Y. Li, H. Liu, Y. Wang, Q. Chang, W. Jiao, and Y. Song, “Saturable absorption and reverse saturable absorption in platinum nanoparticles,” Opt. Commun. 251, 429–433 (2005).
[CrossRef]

Opt. Express

Opt. Quantum Electron.

T.-H. Wei and T.-H. Huang, “A study of photophysics using the Z-scan technique: lifetime determination for high-lying excited states,” Opt. Quantum Electron. 28, 1495–1508 (1996).
[CrossRef]

Plasmonics

J. Lakowicz, “Plasmonics in biology and plasmon-controlled fluorescence,” Plasmonics 1, 5–33 (2006).
[CrossRef]

Science

R. R. Nair, P. Blake, A. N. Grigorenko, K. S. Novoselov, T. J. Booth, T. Stauber, N. M. R. Peres, and A. K. Geim, “Fine structure constant defines visual transparency of graphene,” Science 320, 1308 (2008).
[CrossRef]

K. S. Novoselov, A. K. Geim, S. V. Morozov, D. Jiang, Y. Zhang, S. V. Dubonos, I. V. Grigorieva, and A. A. Firsov, “Electric field effect in atomically thin carbon films,” Science 306, 666–669 (2004).
[CrossRef]

J. R. Williams, L. DiCarlo, and C. M. Marcus, “Quantum hall effect in a gate-controlled p-n junction of graphene,” Science 317, 638–641 (2007).
[CrossRef]

A. P. Alivisatos, “Semiconductor clusters, nanocrystals, and quantum dots,” Science 271, 933–937 (1996).
[CrossRef]

D. Li and R. B. Kaner, “Graphene-based materials,” Science 320, 1170–1171 (2008).
[CrossRef]

Small

G. G. Wildgoose, C. E. Banks, and R. G. Compton, “Metal nanoparticles and related materials supported on carbon nanotubes: methods and applications,” Small 2, 182–193 (2006).
[CrossRef]

Other

A. E. Siegman, Lasers (University Science, 1986).

Cited By

OSA participates in CrossRef's Cited-By Linking service. Citing articles from OSA journals and other participating publishers are listed here.

Alert me when this article is cited.


Figures (8)

Fig. 1.
Fig. 1.

Experimental setup for Z-scan for measuring the nonlinear absorption and scattering. L, lens; S, sample; D1, D2, photodiodes.

Fig. 2.
Fig. 2.

Absorption spectrum of (a) fG and (b) AgNP/fG in ethylene glycol. Curve (c) gives the Gaussian analysis of the plasmonic peak at 420 nm and curve (d) is the absorption spectrum of solvent.

Fig. 3.
Fig. 3.

(a) XRD pattern and (b) Raman spectrum of AgNP/fG and fG.

Fig. 4.
Fig. 4.

(a) TEM image of graphene composite. The encircled area shows the nearly uniform distribution of AgNPs. (b) Magnified image used for size determination of AgNPs.

Fig. 5.
Fig. 5.

OA Z-scan profile of the (a) AgNP/fG, (b) fG, and (c) AgNPs at 1064 nm at different pump energies with constant concentration 1mg/ml. Inset of (a) shows the ratio of CA to OA profiles (with error bars of 10%) at an intensity of 45GW/cm2. (d) OA Z-scan profile of SA IR26 in 1,2 di-chloroethane.

Fig. 6.
Fig. 6.

OA Z-scan profile of (a) AgNP/fG, (b) fG, and (c) AgNPs at 532 nm at different pump energies with constant concentration of 1mg/ml.

Fig. 7.
Fig. 7.

Energy diagram of the metal–graphene interface and resulting Fermi level with respect to the Dirac point. Fermi level EF shifts due to the charge transfer, the work function of the metal (φM=5.0eV), and graphene (φG=4.5eV) are also indicated. ΔW is caused by the charge built up at the interface.

Fig. 8.
Fig. 8.

OL properties of AgNP/fG, fG, and AgNPs at 1064 nm.

Tables (1)

Tables Icon

Table 1. Optical Nonlinear Properties of AgNP/fG, fG, and AgNPs

Equations (4)

Equations on this page are rendered with MathJax. Learn more.

I(z,r,t)=I0[ω0ω(z)]2exp[2r2ω(z)2]exp[t2τ02].
α(I)=αo1+I/Is+βI,
dIdl=α(I)I.
T(z)=m=0[q]m(1+m)3/2,

Metrics