Abstract

We introduce an innovative high-sensitivity broadband pump-probe spectroscopy system, based on Fourier-transform detection, operating at 20-MHz modulation frequency. A common-mode interferometer employing birefringent wedges creates two phase-locked delayed replicas of the broadband probe pulse, interfering at a single photodetector. A single-channel lock-in amplifier demodulates the interferogram, whose Fourier transform provides the differential transmission spectrum. Our approach combines broad spectral coverage with high sensitivity, due to high-frequency modulation and detection. We demonstrate its performances by measuring two-dimensional differential transmission maps of a carbon nanotubes sample, simultaneously acquiring the signal over the entire 950–1350 nm range with 2.7·106rms noise over 1.5 s integration time.

© 2016 Optical Society of America

Pump-probe is the most versatile and widely used ultrafast spectroscopy technique, which allows for measurement of the excited-state dynamics of a great variety of samples [1]. In pump-probe an energetic pump pulse, resonant with a transition of the system under study, promotes population from the ground to the excited state; the subsequent system evolution is monitored by measuring the transmission change of a weak probe pulse, as a function of the pump-probe delay τ [2]. To maximize information on the system dynamics, the signal should be detected for several transition energies; this is typically accomplished by using a broadband probe pulse, and measuring the wavelength-(λpr) and delay-(τ) dependent differential transmission signal ΔT/T(λpr,τ). To this end, two approaches are possible: a serial one, which measures ΔT/T dynamics at individual probe wavelengths, and obtains the ΔT/T(λpr,τ) map by stacking the time traces together; and a parallel one, which uses a spectrometer to separate the different frequency components of the probe pulse and then measuring them simultaneously with a multichannel detector. The parallel approach is preferable because it greatly reduces the measurement time and it minimizes distortions in the retrieved spectra that could arise from slow drifts in the pump power, gradual sample damage or gradual misalignment of the detection chain or the spatial overlap of the two pulses.

ΔT/T signals in pump-probe are typically very small and lie on a large background, so they require modulation transfer techniques for their measurement. These techniques consist of: (i) amplitude modulation of the pump through a mechanical chopper, or an acousto-optic or an electro-optic modulator, ideally at a frequency exactly locked to half the repetition rate of the laser, so as to benefit from the enhanced energy correlation of consecutive laser pulses; and (ii) synchronous demodulation of the probe to detect the pump-induced transmission changes. The sensitivity of pump-probe depends on the repetition rate of the system: it is 104/105 for high-pulse-energy amplified laser systems running at kHz repetition rate [211] and 106/107 for low-energy laser oscillators running at MHz repetition rate [12].

For kHz lasers parallel detection is straightforward to implement, using an optical multichannel analyzer (OMA), which consists of an imaging spectrometer that disperses the broadband probe beam onto a multi-channel line camera (either a CCD or an array of photodiodes) capable of single-shot detection at the full laser repetition rate [211]. The single-shot sensitivity of the detection chain (not considering the laser fluctuations) is typically limited to ΔT/T103 per spectrum by an interplay of the electronic/read-out noise of the camera and the shot noise associated with the 105106 electrons’ full-well capacity of the individual pixels. Using a camera running at 10-kHz readout frequency and a very stable laser source, Liebel et al. [10] demonstrated sensitivities down to ΔT/T<105 within 1-s measurement time. Analogously, Kanal et al. [11] presented a pump-probe scheme based on a fast camera with 100-kHz readout frequency, which provides single-shot sensitivity of 7.5·103 in absorbance change, limited by the laser intensity fluctuations, and translating into ΔT/T6·105 within 1-s measurement time.

For MHz lasers no OMAs capable of single-shot detection exist, so the serial approach is typically used, measuring ΔT/T dynamics at individual probe wavelengths, selected by an interference filter or a monochromator, and using a photodiode connected to a high-frequency lock-in amplifier. Multi-channel lock-in amplifiers have been proposed, but they are expensive, with limited channel number and/or repetition rate, and bulky and complicated setups [13,14].

In this Letter we introduce a new approach to broadband pump-probe spectroscopy, based on time-domain Fourier-transform (FT) detection and employing a single detector combined with a high-frequency modulator and lock-in amplifier. After the sample, the broadband probe pulse is sent to a linear interferometer that creates two collinear replicas with relative delay t. The two replicas interfere on the detector, giving rise to an interferogram, whose FT with respect to t is the spectrum of the unperturbed probe pulse [15]. Owing to the linearity of the FT operator, the FT of the interferogram of the ΔT signal, as recorded by the lock-in, gives the ΔT spectrum. Our approach has the advantage of combining broad spectral coverage, due to the FT detection, and high sensitivity, due to the high frequency (up to 20 MHz, i.e., half the repetition rate of the laser) modulation and detection. Scanning the delay line only once per ΔT/T(λpr,τ) map also speeds up collection with respect to the serial approach since the acquisition is blocked during movement.

A conceptual scheme of the experimental setup is shown in Fig. 1. A femtosecond laser source provides both the pump beam, resonant with the sample absorption, and the broadband probe beam, covering the spectral bandwidth of interest. The pump is sent to a motorized translation stage for delay control (M-405.CG from Physik Instrumente) and to an amplitude modulator for synchronous detection. Pump and probe beams are focused on the sample in a non-collinear geometry. After the sample, the probe light is selected by an iris and sent to a birefringent interferometer, which is a simplified version [16] of the Translating-Wedge-based Identical pulses eNcoding System (TWINS), previously introduced by some of the authors [17]. It consists of two birefringent wedges and a birefringent plate, with perpendicular orientation of their optical axes (as indicated in yellow in Fig. 1); the incoming pulse, polarized at 45° with respect to the directions of the optical axes is split into two delayed pulses with perpendicular polarization. A polarizer before the TWINS can be inserted to control the polarization of the probe beam in case of depolarization induced by the sample birefringence or other spurious effects. This configuration is equivalent to a Babinet–Soleil compensator, with the difference that, while the Babinet–Soleil compensator is typically used as a variable waveplate, generating a retardation of one or a few cycles, TWINS provides retardation of hundreds of optical cycles, thus working as a pulse pair generator. Because of the inherent phase stability of the common-mode TWINS interferometer, the two delayed replicas are phase-locked with stability better than λ/100, enabling us to measure interferograms extremely accurately. The delay between the two replicas can be easily controlled by moving one wedge with a motorized translation stage (LMS-60 from Physik Instrumente). The direction of movement (see blue arrow in Fig. 1) is chosen to keep constant the distance of the two wedges, thus avoiding any displacement of the output beam. We measured only during the forward movement of the wedge, which was then sent back to its starting position at high speed (60mm/s) in parallel with the movement of the pump-probe delay stage. The optical axis of the fixed birefringent plate is perpendicular with respect to the one of the wedges, so that it reverts the relative delays of the two replicas. Moreover, its thickness is intermediate between the total thickness of the two wedges at maximum and minimum insertion, thus enabling us to scan across zero relative delay and record symmetric interferograms.

 figure: Fig. 1.

Fig. 1. Schematic drawing of the setup. WP, Wollaston prism; BPD, balanced photodiode; ADC, analog-to-digital conversion board. The directions of the optical axis of the birefringent materials in TWINS are indicated in yellow. The blue and black arrows indicate the direction of movement of translating stages.

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After the TWINS, a Wollaston prism (WP10 from Thorlabs) oriented at 45° with respect to the optical axis of the wedges separates the probe into two orthogonally polarized beams, each containing an interferogram (generated by the interference between the two pulse replicas) but with a relative phase shift of π. The two generated beams are eventually measured with the photodiodes of a balanced detector (Thorlabs PDB450A for the visible and PDB450C for the infrared). Since the balanced output of the detector is the difference between the two input channels, the common-mode signal is cancelled out, resulting in an interferogram with doubled amplitude and zero offset. Alternatively, one can replace the Wollaston prism can be replaced with a polarizer oriented at 45° and a single-channel photodiode used, thus simplifying the experimental configuration at the cost of reducing the amplitude of the measured interferogram. The AC output of the balanced photodiode is sent to a high-frequency lock-in amplifier (HF2LI from Zurich Instruments). An analog-to-digital conversion card simultaneously records the demodulated signal from the lock-in and the DC output of the photodiode (as illustrated in Fig. 1) as a function of the wedge position xw. These two waveforms are called the differential interferogram ΔT(xw) and the linear probe interferogram T(xw), respectively. We first apply a super-Gaussian apodization window, to remove spectral side lobes caused by the finite sampled temporal interval, and then we compute their FTs, thus obtaining the differential transmission spectrum ΔT(λpr,τ) and the linear transmission spectrum T(λpr) of the sample. A proper calibration is required to retrieve the wavelength axis from the FT frequency axis. To this purpose interpolation can be performed that will not cross the origin due to the partially rotating frame [17], using a series of interference filters or a sample with a structured transmission spectrum [16]. The main advantage of this procedure is that, due to the linearity of the FT operator, to retrieve the ΔT(λpr,τ) spectrum we do not need to record two interferograms of the perturbed and unperturbed sample and compute the difference of their FTs; instead, we can just record the interferogram of the ΔT signal, measured by the lock-in, and compute its FT. This approach was already demonstrated for broadband stimulated Raman scattering (SRS) microscopy [18]. By repeating this procedure at different delays, one can then build the two-dimensional ΔT/T(λpr,τ) map can be built.

Particular attention must be paid to the phasing of the interferograms. Slight shifts of the zero-delay position would indeed cause serious errors in the retrieved spectral line shapes. By definition, interferograms should be symmetric functions, but experimental errors—such as electronic noise, laser fluctuations, misalignment of the detection chain, or irregularities in the moving parts—can introduce asymmetries. Moreover, the lock-in amplifier is a signal integrator with finite response time, depending on the selected time constant. We typically set it to a value 100 times smaller than the time required for the wedge to scan a fringe of the interferogram, of the order of 100 μs. Nonetheless, the differential interferogram ΔT(xw) is still affected by a non-negligible delay with respect to the linear probe interferogram T(xw), because the latter directly comes from the photodiode with no delay. Therefore, we took special care in: (i) designing a proper phasing algorithm that finds the peak of the self-convolution of an interferogram to flatten its FT phase around zero or π; and (ii) calibrating the delay introduced by the lock-in amplifier and numerically compensating for it. The latter procedure is performed only once around zero pump-probe delay (where the ΔT signal is highest) accurately measuring the difference of the zero-delay positions [estimated by the phasing algorithm (i)] between the linear and differential interferogram, which is then kept fixed for the other pump-probe delays. This procedure is not necessary in SRS spectroscopy, for which, in contrast to pump-probe, the signal does not change in sign, so the modulus of the FT (that does not depend on the phasing of the interferogram) can be plotted instead of its real part [18].

The spectral resolution of the retrieved signal is Δν=1/tmax, where tmax is the maximum delay between the two replicas. This delay is given by tmax=GVM·d, where GVM=(1/vge1/vgo) is the group velocity mismatch, vgo and vge are the group velocities for the ordinary and extraordinary polarizations, respectively, and d is the thickness of the birefringent material [17]. To improve the spectral resolution one can act either on the birefringent material, which affects the GVM for the specific wavelengths of interest, or on the apex angle α and travel range L of the moving wedge that determine the maximum thickness d=Ltanα (in the hypothesis that the beam size is much smaller than L). We employed alpha-barium borate (α-BBO) wedges with apex angle α=7° and 25-mm lateral size that can guarantee a spectral resolution at 1.1 μm down to 5nm.

We first benchmarked our setup against a standard OMA-based pump-probe spectrometer for a low-repetition-rate laser. To this purpose, we measured ΔT/T spectra of a β-carotene sample in quinoline solution using an amplified Ti:sapphire laser (Libra from Coherent Inc.), generating 100-fs, 800-nm pulses at 2-kHz repetition rate. The pump pulse was the second harmonic of the laser at 400 nm, modulated at 1-kHz frequency (synchronized with the laser clock) by a mechanical chopper, while the probe was a white-light supercontinuum generated in a 2-mm sapphire plate. Figure 2 plots as black squares the ΔT/T spectrum, at 1-ps pump-probe delay, measured using a standard OMA detection scheme [3] and as a red solid line the ΔT/T spectrum collected with our TWINS-based FT spectrometer under the same experimental conditions. The agreement is excellent, thus demonstrating the reliability of our new detection system for broadband pump-probe spectroscopy. We observe the well-known transient absorption signals of β-carotene [19]: photo-bleaching (ΔT/T>0) of the transition from the ground-state to the first optically allowed S2 state for wavelengths shorter than 525 nm, and photo-induced absorption (ΔT/T<0) from the dark S1 state to a higher-lying Sn state, peaking at 590nm wavelength.

 figure: Fig. 2.

Fig. 2. Comparison of ΔT/T spectra collected on a β-carotene sample in solution at the same 1-ps delay using a standard OMA based on a CCD camera (squares) and the FT procedure introduced here (solid red line). Hashed area: probe spectrum.

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We then applied our approach to a high-repetition-rate laser system, for which no single-shot multi-channel detectors are available. We employed an Erbium-fiber oscillator (FemtoFiber Pro from Toptica Photonics), providing 70-fs pulses at 1.55-μm central wavelength and 40-MHz repetition rate. The output beam is divided into two branches, each amplified to 350-mW average power by two independent Er-doped fiber amplifiers (EDFAs). The output of the first EDFA is sent to a 2-mm-thick beta-barium borate (BBO) crystal, generating the pump pulse at the second harmonic (λ=780nm). The pump beam is then sent to an acousto-optic modulator working at 20-MHz frequency (synchronized with the laser clock). The output of the second EDFA feeds a highly nonlinear fiber, which broadens the spectrum of the incoming beam, producing a broadband (λ=9401400nm) probe beam [see gray hashed area in Fig. 3(c)].

 figure: Fig. 3.

Fig. 3. (a) Apodized linear (black line) and differential (blue line) interferograms at 100 fs delay, together with the apodization window used. (b) Two-dimensional ΔT/T(λpr,τ) map for a SWNT sample. (c) Solid lines, ΔT/T spectra at selected probe delays as indicated; hashed area, probe spectrum. (d) ΔT/T dynamics (solid lines) and corresponding fits (circles) at selected probe wavelengths (red: λ=1065nm; black: λ=1215nm). Inset: close-up of the signal at λ=1215nm for negative delays.

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We measured ΔT/T dynamics on a spin-coated sample of semiconducting single-walled carbon nanotubes (SWNTs) starting from a highly concentrated dispersion in orthodichlorobenzene [20]. The resulting sample presents a large number of bundles and aggregates, with a predominance of the (6,5) and the (7,5) chiralities, resulting in a broad absorption band of the first excitonic transition (S11) centered at 1060 nm. Since no sharp spectral features are expected in the ΔT/T spectra, we aimed at a coarse spectral resolution of 50 nm, to maximize the recording speed. Therefore, we limited the TWINS travel range to L=3mm, resulting in tmax=±75fs maximum delay of the replicas. The wedge was translated at 6 mm/s constant speed, thus resulting in 0.5s measurement time for each ΔT/T spectrum. Increasing the scan range to L=15mm achieving 10-nm spectral resolution at the cost of increasing the measurement time to 2.5-s per spectrum would also be possible. Representative linear T(xw) and differential ΔT(xw) interferograms at τ=100fs delay are reported in Fig. 3(a), together with the apodization window used.

In Fig. 3(b) we plot the two-dimensional ΔT/T(λpr,τ) map, resulting from the average of three time scans. ΔT/T spectra at selected delays (100 fs, 1 ps, and 3.5 ps) are plotted in Fig. 3(c) as solid lines. After photoexcitation, we see a strong positive signal, peaking at λ=1065nm, due to ground-state photo-bleaching of the first excitonic transition of the SWNTs; this decays on the ps-timescale due to non-radiative ground-state recovery [21], with no significant change in the spectral profile. To highlight the population dynamics in the SWNT sample, we report as solid lines in Fig. 3(d) ΔT/T time traces at the peak of the signal (λ=1065nm, red) and on its red-shifted shoulder (λ=1215nm, black). Circles in Fig. 3(d) are fits to the data, using a simple sequential three-level rate-equation model to the single dynamics, typical of SWNTs, convoluted with the 500-fs instrumental response function. The results indicate that excited-state population decays with a fast (150–180 fs) and a slow (1–3 ps, depending on the wavelength) time constant, in accordance with previous literature [22].

The real advantage of our detection scheme consists in running at high modulation frequencies, where the laser relative intensity noise is typically the lowest. This is clear by looking more closely at the dynamics at λ=1215nm (i.e., at the peak of the probe spectrum) and negative delays [see inset of Fig. 3(d)]. The peak-to-peak fluctuations of the signal around zero (with our 1.5-s integration time per delay) are of the order of ±5×106, and the corresponding rms noise is as low as 2.7×106. It should be emphasized that, like several other fiber-based lasers, our system is not shot-noise limited, even at high frequencies [23], but has significant excess noise; using a more stable laser would hence enable us to reduce the rms noise even further.

In conclusion, we have proposed and experimentally demonstrated an innovative detection scheme for pump-probe spectroscopy, which combines a broad spectral coverage with very high modulation frequencies. This enables us to perform broadband measurements with an excellent signal-to-noise ratio in a short time. Our scheme, based on a single detector and lock-in amplifier, is significantly less expensive and complex than other implementations using a high-frequency multi-channel lock-in, which could provide even higher sensitivity. This apparatus relies on the stability of the TWINS interferometer, whose common-path geometry allows control of the delay between two pulses with a precision of attoseconds, without any active control or feedback. Because of this feature, the technique proposed here can be straightforwardly extended to other spectral regions, from the UV to the mid-IR.

Funding

European Research Council (ERC) (ERC-2011-AdG 291198, ERC-2014-CoG 648615, ERC-2014-POC 665635).

REFERENCES

1. S. Mukamel, Principles of Nonlinear Optical Spectroscopy (Oxford University, 1995).

2. U. Megerle, I. Pugliesi, C. Schriever, C. F. Sailer, and E. Riedle, Appl. Phys. B 96, 215 (2009). [CrossRef]  

3. D. Polli, L. Lüer, and G. Cerullo, Rev. Sci. Instrum. 78, 103108 (2007). [CrossRef]  

4. A. L. Dobryakov, S. A. Kovalenko, A. Weigel, J. L. Pérez-Lustres, J. Lange, A. Müller, and N. P. Ernsting, Rev. Sci. Instrum. 81, 113106 (2010). [CrossRef]  

5. M. Bradler and E. Riedle, J. Opt. Soc. Am. B 31, 1465 (2014). [CrossRef]  

6. A. Wand, R. Rozin, T. Eliash, K.-H. Jung, M. Sheves, and S. Ruhman, J. Am. Chem. Soc. 133, 20922 (2011). [CrossRef]  

7. A. Maciejewski, R. Naskrecki, M. Lorenc, M. Ziolek, J. Karolczak, J. Kubicki, M. Matysiak, and M. Szymanski, J. Mol. Struct. 555, 1 (2000). [CrossRef]  

8. M. Raytchev, E. Pandurski, I. Buchvarov, C. Modrakowski, and T. Fiebig, J. Phys. Chem. A 107, 4592 (2003). [CrossRef]  

9. S. Bourquin, R. P. Prasankumar, F. X. Kärtner, J. G. Fujimoto, T. Lasser, and R. P. Salathé, Opt. Lett. 28, 1588 (2003). [CrossRef]  

10. F. M. Liebel, C. Schnedermann, T. Wende, and P. Kukura, J. Phys. Chem. 119, 9506 (2015). [CrossRef]  

11. F. Kanal, S. Keiber, R. Eck, and T. Brixner, Opt. Express 22, 16965 (2014). [CrossRef]  

12. H. Baida, D. Mongin, D. Christofilos, G. Bachelier, A. Crut, P. Maioli, N. Del Fatti, and F. Vallée, Phys. Rev. Lett. 107, 057402 (2011). [CrossRef]  

13. C.-W. Luo, Y.-T. Wang, A. Yabushita, and T. Kobayashi, Optica 3, 82 (2016). [CrossRef]  

14. N. Ishii, E. Tokunaga, S. Adachi, T. Kimura, H. Matsuda, and T. Kobayashi, Phys. Rev. A 70, 023811 (2004). [CrossRef]  

15. B. C. Smith, Fundamentals of Fourier Transform Infrared Spectroscopy (CRC Press, 2011).

16. A. Oriana, J. Réhault, F. Preda, D. Polli, and G. Cerullo, J. Opt. Soc. Am. A (submitted).

17. D. Brida, C. Manzoni, and G. Cerullo, Opt. Lett. 37, 3027 (2012). [CrossRef]  

18. J. Réhault, F. Crisafi, V. Kumar, G. Ciardi, M. Marangoni, G. Cerullo, and D. Polli, Opt. Express 23, 25235 (2015). [CrossRef]  

19. T. Polívka and V. Sundström, Chem. Rev. 104, 2021 (2004). [CrossRef]  

20. L. N. Glanzmann, D. J. Mowbray, D. G. Figueroa del Valle, F. Scotognella, G. Lanzani, and A. Rubio, J. Phys. Chem. C 120, 1926 (2016). [CrossRef]  

21. J.-S. Lauret, C. Voisin, G. Cassabois, C. Delalande, Ph. Roussignol, O. Jost, and L. Capes, Phys. Rev. Lett. 90, 057404 (2003). [CrossRef]  

22. L. Lüer, S. Hoseinkhani, D. Polli, J. Crochet, T. Hertel, and G. Lanzani, Nat. Phys. 5, 54 (2009). [CrossRef]  

23. N. Coluccelli, V. Kumar, M. Cassinerio, G. Galzerano, M. Marangoni, and G. Cerullo, Opt. Lett. 39, 3090 (2014). [CrossRef]  

References

  • View by:

  1. S. Mukamel, Principles of Nonlinear Optical Spectroscopy (Oxford University, 1995).
  2. U. Megerle, I. Pugliesi, C. Schriever, C. F. Sailer, and E. Riedle, Appl. Phys. B 96, 215 (2009).
    [Crossref]
  3. D. Polli, L. Lüer, and G. Cerullo, Rev. Sci. Instrum. 78, 103108 (2007).
    [Crossref]
  4. A. L. Dobryakov, S. A. Kovalenko, A. Weigel, J. L. Pérez-Lustres, J. Lange, A. Müller, and N. P. Ernsting, Rev. Sci. Instrum. 81, 113106 (2010).
    [Crossref]
  5. M. Bradler and E. Riedle, J. Opt. Soc. Am. B 31, 1465 (2014).
    [Crossref]
  6. A. Wand, R. Rozin, T. Eliash, K.-H. Jung, M. Sheves, and S. Ruhman, J. Am. Chem. Soc. 133, 20922 (2011).
    [Crossref]
  7. A. Maciejewski, R. Naskrecki, M. Lorenc, M. Ziolek, J. Karolczak, J. Kubicki, M. Matysiak, and M. Szymanski, J. Mol. Struct. 555, 1 (2000).
    [Crossref]
  8. M. Raytchev, E. Pandurski, I. Buchvarov, C. Modrakowski, and T. Fiebig, J. Phys. Chem. A 107, 4592 (2003).
    [Crossref]
  9. S. Bourquin, R. P. Prasankumar, F. X. Kärtner, J. G. Fujimoto, T. Lasser, and R. P. Salathé, Opt. Lett. 28, 1588 (2003).
    [Crossref]
  10. F. M. Liebel, C. Schnedermann, T. Wende, and P. Kukura, J. Phys. Chem. 119, 9506 (2015).
    [Crossref]
  11. F. Kanal, S. Keiber, R. Eck, and T. Brixner, Opt. Express 22, 16965 (2014).
    [Crossref]
  12. H. Baida, D. Mongin, D. Christofilos, G. Bachelier, A. Crut, P. Maioli, N. Del Fatti, and F. Vallée, Phys. Rev. Lett. 107, 057402 (2011).
    [Crossref]
  13. C.-W. Luo, Y.-T. Wang, A. Yabushita, and T. Kobayashi, Optica 3, 82 (2016).
    [Crossref]
  14. N. Ishii, E. Tokunaga, S. Adachi, T. Kimura, H. Matsuda, and T. Kobayashi, Phys. Rev. A 70, 023811 (2004).
    [Crossref]
  15. B. C. Smith, Fundamentals of Fourier Transform Infrared Spectroscopy (CRC Press, 2011).
  16. A. Oriana, J. Réhault, F. Preda, D. Polli, and G. Cerullo, J. Opt. Soc. Am. A (submitted).
  17. D. Brida, C. Manzoni, and G. Cerullo, Opt. Lett. 37, 3027 (2012).
    [Crossref]
  18. J. Réhault, F. Crisafi, V. Kumar, G. Ciardi, M. Marangoni, G. Cerullo, and D. Polli, Opt. Express 23, 25235 (2015).
    [Crossref]
  19. T. Polívka and V. Sundström, Chem. Rev. 104, 2021 (2004).
    [Crossref]
  20. L. N. Glanzmann, D. J. Mowbray, D. G. Figueroa del Valle, F. Scotognella, G. Lanzani, and A. Rubio, J. Phys. Chem. C 120, 1926 (2016).
    [Crossref]
  21. J.-S. Lauret, C. Voisin, G. Cassabois, C. Delalande, Ph. Roussignol, O. Jost, and L. Capes, Phys. Rev. Lett. 90, 057404 (2003).
    [Crossref]
  22. L. Lüer, S. Hoseinkhani, D. Polli, J. Crochet, T. Hertel, and G. Lanzani, Nat. Phys. 5, 54 (2009).
    [Crossref]
  23. N. Coluccelli, V. Kumar, M. Cassinerio, G. Galzerano, M. Marangoni, and G. Cerullo, Opt. Lett. 39, 3090 (2014).
    [Crossref]

2016 (2)

C.-W. Luo, Y.-T. Wang, A. Yabushita, and T. Kobayashi, Optica 3, 82 (2016).
[Crossref]

L. N. Glanzmann, D. J. Mowbray, D. G. Figueroa del Valle, F. Scotognella, G. Lanzani, and A. Rubio, J. Phys. Chem. C 120, 1926 (2016).
[Crossref]

2015 (2)

2014 (3)

2012 (1)

2011 (2)

A. Wand, R. Rozin, T. Eliash, K.-H. Jung, M. Sheves, and S. Ruhman, J. Am. Chem. Soc. 133, 20922 (2011).
[Crossref]

H. Baida, D. Mongin, D. Christofilos, G. Bachelier, A. Crut, P. Maioli, N. Del Fatti, and F. Vallée, Phys. Rev. Lett. 107, 057402 (2011).
[Crossref]

2010 (1)

A. L. Dobryakov, S. A. Kovalenko, A. Weigel, J. L. Pérez-Lustres, J. Lange, A. Müller, and N. P. Ernsting, Rev. Sci. Instrum. 81, 113106 (2010).
[Crossref]

2009 (2)

U. Megerle, I. Pugliesi, C. Schriever, C. F. Sailer, and E. Riedle, Appl. Phys. B 96, 215 (2009).
[Crossref]

L. Lüer, S. Hoseinkhani, D. Polli, J. Crochet, T. Hertel, and G. Lanzani, Nat. Phys. 5, 54 (2009).
[Crossref]

2007 (1)

D. Polli, L. Lüer, and G. Cerullo, Rev. Sci. Instrum. 78, 103108 (2007).
[Crossref]

2004 (2)

N. Ishii, E. Tokunaga, S. Adachi, T. Kimura, H. Matsuda, and T. Kobayashi, Phys. Rev. A 70, 023811 (2004).
[Crossref]

T. Polívka and V. Sundström, Chem. Rev. 104, 2021 (2004).
[Crossref]

2003 (3)

J.-S. Lauret, C. Voisin, G. Cassabois, C. Delalande, Ph. Roussignol, O. Jost, and L. Capes, Phys. Rev. Lett. 90, 057404 (2003).
[Crossref]

M. Raytchev, E. Pandurski, I. Buchvarov, C. Modrakowski, and T. Fiebig, J. Phys. Chem. A 107, 4592 (2003).
[Crossref]

S. Bourquin, R. P. Prasankumar, F. X. Kärtner, J. G. Fujimoto, T. Lasser, and R. P. Salathé, Opt. Lett. 28, 1588 (2003).
[Crossref]

2000 (1)

A. Maciejewski, R. Naskrecki, M. Lorenc, M. Ziolek, J. Karolczak, J. Kubicki, M. Matysiak, and M. Szymanski, J. Mol. Struct. 555, 1 (2000).
[Crossref]

Adachi, S.

N. Ishii, E. Tokunaga, S. Adachi, T. Kimura, H. Matsuda, and T. Kobayashi, Phys. Rev. A 70, 023811 (2004).
[Crossref]

Bachelier, G.

H. Baida, D. Mongin, D. Christofilos, G. Bachelier, A. Crut, P. Maioli, N. Del Fatti, and F. Vallée, Phys. Rev. Lett. 107, 057402 (2011).
[Crossref]

Baida, H.

H. Baida, D. Mongin, D. Christofilos, G. Bachelier, A. Crut, P. Maioli, N. Del Fatti, and F. Vallée, Phys. Rev. Lett. 107, 057402 (2011).
[Crossref]

Bourquin, S.

Bradler, M.

Brida, D.

Brixner, T.

Buchvarov, I.

M. Raytchev, E. Pandurski, I. Buchvarov, C. Modrakowski, and T. Fiebig, J. Phys. Chem. A 107, 4592 (2003).
[Crossref]

Capes, L.

J.-S. Lauret, C. Voisin, G. Cassabois, C. Delalande, Ph. Roussignol, O. Jost, and L. Capes, Phys. Rev. Lett. 90, 057404 (2003).
[Crossref]

Cassabois, G.

J.-S. Lauret, C. Voisin, G. Cassabois, C. Delalande, Ph. Roussignol, O. Jost, and L. Capes, Phys. Rev. Lett. 90, 057404 (2003).
[Crossref]

Cassinerio, M.

Cerullo, G.

Christofilos, D.

H. Baida, D. Mongin, D. Christofilos, G. Bachelier, A. Crut, P. Maioli, N. Del Fatti, and F. Vallée, Phys. Rev. Lett. 107, 057402 (2011).
[Crossref]

Ciardi, G.

Coluccelli, N.

Crisafi, F.

Crochet, J.

L. Lüer, S. Hoseinkhani, D. Polli, J. Crochet, T. Hertel, and G. Lanzani, Nat. Phys. 5, 54 (2009).
[Crossref]

Crut, A.

H. Baida, D. Mongin, D. Christofilos, G. Bachelier, A. Crut, P. Maioli, N. Del Fatti, and F. Vallée, Phys. Rev. Lett. 107, 057402 (2011).
[Crossref]

Del Fatti, N.

H. Baida, D. Mongin, D. Christofilos, G. Bachelier, A. Crut, P. Maioli, N. Del Fatti, and F. Vallée, Phys. Rev. Lett. 107, 057402 (2011).
[Crossref]

Delalande, C.

J.-S. Lauret, C. Voisin, G. Cassabois, C. Delalande, Ph. Roussignol, O. Jost, and L. Capes, Phys. Rev. Lett. 90, 057404 (2003).
[Crossref]

Dobryakov, A. L.

A. L. Dobryakov, S. A. Kovalenko, A. Weigel, J. L. Pérez-Lustres, J. Lange, A. Müller, and N. P. Ernsting, Rev. Sci. Instrum. 81, 113106 (2010).
[Crossref]

Eck, R.

Eliash, T.

A. Wand, R. Rozin, T. Eliash, K.-H. Jung, M. Sheves, and S. Ruhman, J. Am. Chem. Soc. 133, 20922 (2011).
[Crossref]

Ernsting, N. P.

A. L. Dobryakov, S. A. Kovalenko, A. Weigel, J. L. Pérez-Lustres, J. Lange, A. Müller, and N. P. Ernsting, Rev. Sci. Instrum. 81, 113106 (2010).
[Crossref]

Fiebig, T.

M. Raytchev, E. Pandurski, I. Buchvarov, C. Modrakowski, and T. Fiebig, J. Phys. Chem. A 107, 4592 (2003).
[Crossref]

Figueroa del Valle, D. G.

L. N. Glanzmann, D. J. Mowbray, D. G. Figueroa del Valle, F. Scotognella, G. Lanzani, and A. Rubio, J. Phys. Chem. C 120, 1926 (2016).
[Crossref]

Fujimoto, J. G.

Galzerano, G.

Glanzmann, L. N.

L. N. Glanzmann, D. J. Mowbray, D. G. Figueroa del Valle, F. Scotognella, G. Lanzani, and A. Rubio, J. Phys. Chem. C 120, 1926 (2016).
[Crossref]

Hertel, T.

L. Lüer, S. Hoseinkhani, D. Polli, J. Crochet, T. Hertel, and G. Lanzani, Nat. Phys. 5, 54 (2009).
[Crossref]

Hoseinkhani, S.

L. Lüer, S. Hoseinkhani, D. Polli, J. Crochet, T. Hertel, and G. Lanzani, Nat. Phys. 5, 54 (2009).
[Crossref]

Ishii, N.

N. Ishii, E. Tokunaga, S. Adachi, T. Kimura, H. Matsuda, and T. Kobayashi, Phys. Rev. A 70, 023811 (2004).
[Crossref]

Jost, O.

J.-S. Lauret, C. Voisin, G. Cassabois, C. Delalande, Ph. Roussignol, O. Jost, and L. Capes, Phys. Rev. Lett. 90, 057404 (2003).
[Crossref]

Jung, K.-H.

A. Wand, R. Rozin, T. Eliash, K.-H. Jung, M. Sheves, and S. Ruhman, J. Am. Chem. Soc. 133, 20922 (2011).
[Crossref]

Kanal, F.

Karolczak, J.

A. Maciejewski, R. Naskrecki, M. Lorenc, M. Ziolek, J. Karolczak, J. Kubicki, M. Matysiak, and M. Szymanski, J. Mol. Struct. 555, 1 (2000).
[Crossref]

Kärtner, F. X.

Keiber, S.

Kimura, T.

N. Ishii, E. Tokunaga, S. Adachi, T. Kimura, H. Matsuda, and T. Kobayashi, Phys. Rev. A 70, 023811 (2004).
[Crossref]

Kobayashi, T.

C.-W. Luo, Y.-T. Wang, A. Yabushita, and T. Kobayashi, Optica 3, 82 (2016).
[Crossref]

N. Ishii, E. Tokunaga, S. Adachi, T. Kimura, H. Matsuda, and T. Kobayashi, Phys. Rev. A 70, 023811 (2004).
[Crossref]

Kovalenko, S. A.

A. L. Dobryakov, S. A. Kovalenko, A. Weigel, J. L. Pérez-Lustres, J. Lange, A. Müller, and N. P. Ernsting, Rev. Sci. Instrum. 81, 113106 (2010).
[Crossref]

Kubicki, J.

A. Maciejewski, R. Naskrecki, M. Lorenc, M. Ziolek, J. Karolczak, J. Kubicki, M. Matysiak, and M. Szymanski, J. Mol. Struct. 555, 1 (2000).
[Crossref]

Kukura, P.

F. M. Liebel, C. Schnedermann, T. Wende, and P. Kukura, J. Phys. Chem. 119, 9506 (2015).
[Crossref]

Kumar, V.

Lange, J.

A. L. Dobryakov, S. A. Kovalenko, A. Weigel, J. L. Pérez-Lustres, J. Lange, A. Müller, and N. P. Ernsting, Rev. Sci. Instrum. 81, 113106 (2010).
[Crossref]

Lanzani, G.

L. N. Glanzmann, D. J. Mowbray, D. G. Figueroa del Valle, F. Scotognella, G. Lanzani, and A. Rubio, J. Phys. Chem. C 120, 1926 (2016).
[Crossref]

L. Lüer, S. Hoseinkhani, D. Polli, J. Crochet, T. Hertel, and G. Lanzani, Nat. Phys. 5, 54 (2009).
[Crossref]

Lasser, T.

Lauret, J.-S.

J.-S. Lauret, C. Voisin, G. Cassabois, C. Delalande, Ph. Roussignol, O. Jost, and L. Capes, Phys. Rev. Lett. 90, 057404 (2003).
[Crossref]

Liebel, F. M.

F. M. Liebel, C. Schnedermann, T. Wende, and P. Kukura, J. Phys. Chem. 119, 9506 (2015).
[Crossref]

Lorenc, M.

A. Maciejewski, R. Naskrecki, M. Lorenc, M. Ziolek, J. Karolczak, J. Kubicki, M. Matysiak, and M. Szymanski, J. Mol. Struct. 555, 1 (2000).
[Crossref]

Lüer, L.

L. Lüer, S. Hoseinkhani, D. Polli, J. Crochet, T. Hertel, and G. Lanzani, Nat. Phys. 5, 54 (2009).
[Crossref]

D. Polli, L. Lüer, and G. Cerullo, Rev. Sci. Instrum. 78, 103108 (2007).
[Crossref]

Luo, C.-W.

Maciejewski, A.

A. Maciejewski, R. Naskrecki, M. Lorenc, M. Ziolek, J. Karolczak, J. Kubicki, M. Matysiak, and M. Szymanski, J. Mol. Struct. 555, 1 (2000).
[Crossref]

Maioli, P.

H. Baida, D. Mongin, D. Christofilos, G. Bachelier, A. Crut, P. Maioli, N. Del Fatti, and F. Vallée, Phys. Rev. Lett. 107, 057402 (2011).
[Crossref]

Manzoni, C.

Marangoni, M.

Matsuda, H.

N. Ishii, E. Tokunaga, S. Adachi, T. Kimura, H. Matsuda, and T. Kobayashi, Phys. Rev. A 70, 023811 (2004).
[Crossref]

Matysiak, M.

A. Maciejewski, R. Naskrecki, M. Lorenc, M. Ziolek, J. Karolczak, J. Kubicki, M. Matysiak, and M. Szymanski, J. Mol. Struct. 555, 1 (2000).
[Crossref]

Megerle, U.

U. Megerle, I. Pugliesi, C. Schriever, C. F. Sailer, and E. Riedle, Appl. Phys. B 96, 215 (2009).
[Crossref]

Modrakowski, C.

M. Raytchev, E. Pandurski, I. Buchvarov, C. Modrakowski, and T. Fiebig, J. Phys. Chem. A 107, 4592 (2003).
[Crossref]

Mongin, D.

H. Baida, D. Mongin, D. Christofilos, G. Bachelier, A. Crut, P. Maioli, N. Del Fatti, and F. Vallée, Phys. Rev. Lett. 107, 057402 (2011).
[Crossref]

Mowbray, D. J.

L. N. Glanzmann, D. J. Mowbray, D. G. Figueroa del Valle, F. Scotognella, G. Lanzani, and A. Rubio, J. Phys. Chem. C 120, 1926 (2016).
[Crossref]

Mukamel, S.

S. Mukamel, Principles of Nonlinear Optical Spectroscopy (Oxford University, 1995).

Müller, A.

A. L. Dobryakov, S. A. Kovalenko, A. Weigel, J. L. Pérez-Lustres, J. Lange, A. Müller, and N. P. Ernsting, Rev. Sci. Instrum. 81, 113106 (2010).
[Crossref]

Naskrecki, R.

A. Maciejewski, R. Naskrecki, M. Lorenc, M. Ziolek, J. Karolczak, J. Kubicki, M. Matysiak, and M. Szymanski, J. Mol. Struct. 555, 1 (2000).
[Crossref]

Oriana, A.

A. Oriana, J. Réhault, F. Preda, D. Polli, and G. Cerullo, J. Opt. Soc. Am. A (submitted).

Pandurski, E.

M. Raytchev, E. Pandurski, I. Buchvarov, C. Modrakowski, and T. Fiebig, J. Phys. Chem. A 107, 4592 (2003).
[Crossref]

Pérez-Lustres, J. L.

A. L. Dobryakov, S. A. Kovalenko, A. Weigel, J. L. Pérez-Lustres, J. Lange, A. Müller, and N. P. Ernsting, Rev. Sci. Instrum. 81, 113106 (2010).
[Crossref]

Polívka, T.

T. Polívka and V. Sundström, Chem. Rev. 104, 2021 (2004).
[Crossref]

Polli, D.

J. Réhault, F. Crisafi, V. Kumar, G. Ciardi, M. Marangoni, G. Cerullo, and D. Polli, Opt. Express 23, 25235 (2015).
[Crossref]

L. Lüer, S. Hoseinkhani, D. Polli, J. Crochet, T. Hertel, and G. Lanzani, Nat. Phys. 5, 54 (2009).
[Crossref]

D. Polli, L. Lüer, and G. Cerullo, Rev. Sci. Instrum. 78, 103108 (2007).
[Crossref]

A. Oriana, J. Réhault, F. Preda, D. Polli, and G. Cerullo, J. Opt. Soc. Am. A (submitted).

Prasankumar, R. P.

Preda, F.

A. Oriana, J. Réhault, F. Preda, D. Polli, and G. Cerullo, J. Opt. Soc. Am. A (submitted).

Pugliesi, I.

U. Megerle, I. Pugliesi, C. Schriever, C. F. Sailer, and E. Riedle, Appl. Phys. B 96, 215 (2009).
[Crossref]

Raytchev, M.

M. Raytchev, E. Pandurski, I. Buchvarov, C. Modrakowski, and T. Fiebig, J. Phys. Chem. A 107, 4592 (2003).
[Crossref]

Réhault, J.

J. Réhault, F. Crisafi, V. Kumar, G. Ciardi, M. Marangoni, G. Cerullo, and D. Polli, Opt. Express 23, 25235 (2015).
[Crossref]

A. Oriana, J. Réhault, F. Preda, D. Polli, and G. Cerullo, J. Opt. Soc. Am. A (submitted).

Riedle, E.

M. Bradler and E. Riedle, J. Opt. Soc. Am. B 31, 1465 (2014).
[Crossref]

U. Megerle, I. Pugliesi, C. Schriever, C. F. Sailer, and E. Riedle, Appl. Phys. B 96, 215 (2009).
[Crossref]

Roussignol, Ph.

J.-S. Lauret, C. Voisin, G. Cassabois, C. Delalande, Ph. Roussignol, O. Jost, and L. Capes, Phys. Rev. Lett. 90, 057404 (2003).
[Crossref]

Rozin, R.

A. Wand, R. Rozin, T. Eliash, K.-H. Jung, M. Sheves, and S. Ruhman, J. Am. Chem. Soc. 133, 20922 (2011).
[Crossref]

Rubio, A.

L. N. Glanzmann, D. J. Mowbray, D. G. Figueroa del Valle, F. Scotognella, G. Lanzani, and A. Rubio, J. Phys. Chem. C 120, 1926 (2016).
[Crossref]

Ruhman, S.

A. Wand, R. Rozin, T. Eliash, K.-H. Jung, M. Sheves, and S. Ruhman, J. Am. Chem. Soc. 133, 20922 (2011).
[Crossref]

Sailer, C. F.

U. Megerle, I. Pugliesi, C. Schriever, C. F. Sailer, and E. Riedle, Appl. Phys. B 96, 215 (2009).
[Crossref]

Salathé, R. P.

Schnedermann, C.

F. M. Liebel, C. Schnedermann, T. Wende, and P. Kukura, J. Phys. Chem. 119, 9506 (2015).
[Crossref]

Schriever, C.

U. Megerle, I. Pugliesi, C. Schriever, C. F. Sailer, and E. Riedle, Appl. Phys. B 96, 215 (2009).
[Crossref]

Scotognella, F.

L. N. Glanzmann, D. J. Mowbray, D. G. Figueroa del Valle, F. Scotognella, G. Lanzani, and A. Rubio, J. Phys. Chem. C 120, 1926 (2016).
[Crossref]

Sheves, M.

A. Wand, R. Rozin, T. Eliash, K.-H. Jung, M. Sheves, and S. Ruhman, J. Am. Chem. Soc. 133, 20922 (2011).
[Crossref]

Smith, B. C.

B. C. Smith, Fundamentals of Fourier Transform Infrared Spectroscopy (CRC Press, 2011).

Sundström, V.

T. Polívka and V. Sundström, Chem. Rev. 104, 2021 (2004).
[Crossref]

Szymanski, M.

A. Maciejewski, R. Naskrecki, M. Lorenc, M. Ziolek, J. Karolczak, J. Kubicki, M. Matysiak, and M. Szymanski, J. Mol. Struct. 555, 1 (2000).
[Crossref]

Tokunaga, E.

N. Ishii, E. Tokunaga, S. Adachi, T. Kimura, H. Matsuda, and T. Kobayashi, Phys. Rev. A 70, 023811 (2004).
[Crossref]

Vallée, F.

H. Baida, D. Mongin, D. Christofilos, G. Bachelier, A. Crut, P. Maioli, N. Del Fatti, and F. Vallée, Phys. Rev. Lett. 107, 057402 (2011).
[Crossref]

Voisin, C.

J.-S. Lauret, C. Voisin, G. Cassabois, C. Delalande, Ph. Roussignol, O. Jost, and L. Capes, Phys. Rev. Lett. 90, 057404 (2003).
[Crossref]

Wand, A.

A. Wand, R. Rozin, T. Eliash, K.-H. Jung, M. Sheves, and S. Ruhman, J. Am. Chem. Soc. 133, 20922 (2011).
[Crossref]

Wang, Y.-T.

Weigel, A.

A. L. Dobryakov, S. A. Kovalenko, A. Weigel, J. L. Pérez-Lustres, J. Lange, A. Müller, and N. P. Ernsting, Rev. Sci. Instrum. 81, 113106 (2010).
[Crossref]

Wende, T.

F. M. Liebel, C. Schnedermann, T. Wende, and P. Kukura, J. Phys. Chem. 119, 9506 (2015).
[Crossref]

Yabushita, A.

Ziolek, M.

A. Maciejewski, R. Naskrecki, M. Lorenc, M. Ziolek, J. Karolczak, J. Kubicki, M. Matysiak, and M. Szymanski, J. Mol. Struct. 555, 1 (2000).
[Crossref]

Appl. Phys. B (1)

U. Megerle, I. Pugliesi, C. Schriever, C. F. Sailer, and E. Riedle, Appl. Phys. B 96, 215 (2009).
[Crossref]

Chem. Rev. (1)

T. Polívka and V. Sundström, Chem. Rev. 104, 2021 (2004).
[Crossref]

J. Am. Chem. Soc. (1)

A. Wand, R. Rozin, T. Eliash, K.-H. Jung, M. Sheves, and S. Ruhman, J. Am. Chem. Soc. 133, 20922 (2011).
[Crossref]

J. Mol. Struct. (1)

A. Maciejewski, R. Naskrecki, M. Lorenc, M. Ziolek, J. Karolczak, J. Kubicki, M. Matysiak, and M. Szymanski, J. Mol. Struct. 555, 1 (2000).
[Crossref]

J. Opt. Soc. Am. B (1)

J. Phys. Chem. (1)

F. M. Liebel, C. Schnedermann, T. Wende, and P. Kukura, J. Phys. Chem. 119, 9506 (2015).
[Crossref]

J. Phys. Chem. A (1)

M. Raytchev, E. Pandurski, I. Buchvarov, C. Modrakowski, and T. Fiebig, J. Phys. Chem. A 107, 4592 (2003).
[Crossref]

J. Phys. Chem. C (1)

L. N. Glanzmann, D. J. Mowbray, D. G. Figueroa del Valle, F. Scotognella, G. Lanzani, and A. Rubio, J. Phys. Chem. C 120, 1926 (2016).
[Crossref]

Nat. Phys. (1)

L. Lüer, S. Hoseinkhani, D. Polli, J. Crochet, T. Hertel, and G. Lanzani, Nat. Phys. 5, 54 (2009).
[Crossref]

Opt. Express (2)

Opt. Lett. (3)

Optica (1)

Phys. Rev. A (1)

N. Ishii, E. Tokunaga, S. Adachi, T. Kimura, H. Matsuda, and T. Kobayashi, Phys. Rev. A 70, 023811 (2004).
[Crossref]

Phys. Rev. Lett. (2)

H. Baida, D. Mongin, D. Christofilos, G. Bachelier, A. Crut, P. Maioli, N. Del Fatti, and F. Vallée, Phys. Rev. Lett. 107, 057402 (2011).
[Crossref]

J.-S. Lauret, C. Voisin, G. Cassabois, C. Delalande, Ph. Roussignol, O. Jost, and L. Capes, Phys. Rev. Lett. 90, 057404 (2003).
[Crossref]

Rev. Sci. Instrum. (2)

D. Polli, L. Lüer, and G. Cerullo, Rev. Sci. Instrum. 78, 103108 (2007).
[Crossref]

A. L. Dobryakov, S. A. Kovalenko, A. Weigel, J. L. Pérez-Lustres, J. Lange, A. Müller, and N. P. Ernsting, Rev. Sci. Instrum. 81, 113106 (2010).
[Crossref]

Other (3)

S. Mukamel, Principles of Nonlinear Optical Spectroscopy (Oxford University, 1995).

B. C. Smith, Fundamentals of Fourier Transform Infrared Spectroscopy (CRC Press, 2011).

A. Oriana, J. Réhault, F. Preda, D. Polli, and G. Cerullo, J. Opt. Soc. Am. A (submitted).

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Figures (3)

Fig. 1.
Fig. 1. Schematic drawing of the setup. WP, Wollaston prism; BPD, balanced photodiode; ADC, analog-to-digital conversion board. The directions of the optical axis of the birefringent materials in TWINS are indicated in yellow. The blue and black arrows indicate the direction of movement of translating stages.
Fig. 2.
Fig. 2. Comparison of Δ T / T spectra collected on a β -carotene sample in solution at the same 1-ps delay using a standard OMA based on a CCD camera (squares) and the FT procedure introduced here (solid red line). Hashed area: probe spectrum.
Fig. 3.
Fig. 3. (a) Apodized linear (black line) and differential (blue line) interferograms at 100 fs delay, together with the apodization window used. (b) Two-dimensional Δ T / T ( λ pr , τ ) map for a SWNT sample. (c) Solid lines, Δ T / T spectra at selected probe delays as indicated; hashed area, probe spectrum. (d)  Δ T / T dynamics (solid lines) and corresponding fits (circles) at selected probe wavelengths (red: λ = 1065 nm ; black: λ = 1215 nm ). Inset: close-up of the signal at λ = 1215 nm for negative delays.

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