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Accepted papers to appear in an upcoming issue

OSA now posts prepublication articles as soon as they are accepted and cleared for production. See the FAQ for additional information.

Pulse propagation in an optically dressed medium in the closed tripod configuration

A Raczynski, Jaroslaw Zaremba, and Sylwia Zielińska-Raczyńska

Doc ID: 235783 Received 06 Mar 2015; Accepted 29 Apr 2015; Posted 29 Apr 2015  View: PDF

Abstract: A probe pulse propagation is examined in a medium irradiated by three control fields in the closed tripod configuration. Those three fields constitute a loop system being in general out of resonance. As a consequence the probe field interacts with the medium dressed in a time-dependent way. Coupled equations for the Floquet components of the probe field are written and solved by diagonalizing the coupling matrix. Examples of numerical solutions are presented and discussed.

Ionization efficiency of Doppler-broadened atoms by transform-limited and broadband nanosecond pulses: one-photon resonant two-photon ionization of muoniums

Rakesh Mohan Das, Takashi Nakajima, Masahiko Iwasaki, and Souvik Chatterjee

Doc ID: 235730 Received 05 Mar 2015; Accepted 26 Apr 2015; Posted 01 May 2015  View: PDF

Abstract: We theoretically study the ionization efficiency of Doppler-broadened atoms through one-photon resonant two-photon ionization process using nanosecond pump and ionizing laser pulses. Under the presence of significant ($>$ tens of GHz) Doppler broadening the bandwidth of the transform-limited nanosecond pump pulse is far smaller than the Doppler width, and the use of the broadband nanosecond pulse rather than the transform-limited nanosecond pulse seems to be much more efficient to pump and eventually ionize atoms. It turns out, however, that the transform-limited nanosecond pump pulse with sufficiently high intensity can outperform the broadband nanosecond pump pulse in the high intensity regime for the ionizing pulse, at which the other broadening mechanisms due to the strong pump and fast ionization play more important roles than the bandwidth itself of the pump pulse. Using a set of density matrix equations we present specific numerical results for muoniums ($\mu^{+}e^{-}$) with enormous Doppler widths (80 and 230 GHz), which support the above argument.

Physics of Broadband Brewster Transmission through Square Array of Rectangular Metallic Pillars

masoud edalatipour, Amin Khavasi, and Khashayar Mehrany

Doc ID: 232616 Received 16 Jan 2015; Accepted 26 Apr 2015; Posted 29 Apr 2015  View: PDF

Abstract: The physics behind the broadband Brewster transmission through square arrays made of rectangular metallic pillars is explored by appealing to the effective medium theory. First, an analytical solution is given for the principal electromagnetic mode propagating between the pillars, and then, the mode matching technique is invoked to extract the parameters of the effective medium model. In this fashion, the pillars are homogenized via a diagonal anisotropic tensor and the effects of higher diffracted orders are included in the effective medium theory by attributing a surface conductivity to the surface boundary of the array. It is shown that the former effectuates the wideband Brewster effect while the latter causes the narrowband spoof surface plasmon resonances. The accuracy of the proposed model is verified by full wave numerical simulations.

Quantum phase estimation using a multi-headed cat state

Su-Yong Lee, Chang-Woo Lee, Hyunchul Nha, and Dagomir Kaszlikowkski

Doc ID: 236148 Received 16 Mar 2015; Accepted 25 Apr 2015; Posted 29 Apr 2015  View: PDF

Abstract: It was recently shown that an entangled coherent state, which is a superposition of two different coherent states, can surpass the performance of N00N state in estimating an unknown phase-shift. This may hint at further enhancement in phase estimation by incorporating more component states in the superposition of resource state. We here study a four-headed cat state (4HCS), a superposition of four different coherent states, and propose its application to quantum phase estimation. We first investigate how the 4HCS is more nonclassical than a 2HCS in view of some nonclassical measures including sub-Poissonian statistics, negativity of Wigner distribution, and entanglement potential. We then demonstrate the enhanced performance in phase estimation by employing an entangled state via the 4HCS, which can surpass that of the 2HCS particularly in the regime of small average photon number. Moreover, we show that an entangled state modified from the 4HCS can further enhance the phase estimation even in the regime of large average photon number under a photon-loss channel. Our investigation further extends to incorporate an increasingly large number of component states in the resource superposition state and clearly show its merit in phase estimation.

Polariton states of cavity coupled three-level atoms

Yifu Zhu, Guo-qing Yang, Zheng Tan, and Bichen zou

Doc ID: 235460 Received 02 Mar 2015; Accepted 25 Apr 2015; Posted 01 May 2015  View: PDF

Abstract: We study a cavity quantum electrodynamics system in which a cavity mode couples simultaneously with two separate transitions of three level atoms, and show that three polariton states are created in the coupled cavity-atom system. We report the observation of such polariton states in an experiment with cold Rb atoms confined in a cavity. The experimental results agree with theoretical calculations based on a semiclassical analysis. The three-level cavity-atom system may be used for a variety of fundamental studies and practical applications.

Large-region tunable optical bistability in a saturable-absorber-based single-frequency Brillouin fiber laser

Li Zhan, Liang Zhang, Minglei Qin, Zhixin Zou, Zhiqiang Wang, and Jinmei Liu

Doc ID: 233533 Received 04 Feb 2015; Accepted 24 Apr 2015; Posted 24 Apr 2015  View: PDF

Abstract: Optical bistability in a saturable-absorber (SA) -based single-frequency Brillouin fiber laser (BFL) is experimentally investigated. Compared with other schemes, the proposed bistable system via a SA-based BFL exhibits large bistable region and tunable optical bistability due to the linewidth-related Brillouin threshold in BFLs. A Sagnac fiber loop consisting of a unpumped Erbium doped fiber (EDF) is embedded in a passive Brillouin fiber laser to serve as the saturable absorber for single-frequency operation. The Stokes lasing power exhibits a hysteresis as varying the pump power. Large-region bistable region is found as 418.8mW in such a SA-based BFL with Brillouin gain media of 50m single mode fiber. Also, the tunability of the bistable region could be implemented by properly designing the Brillouin gain media such as the fiber length and fiber type.

Thermo-mechanical characterization of on-chip buckled dome Fabry-Perot microcavities

Ray DeCorby, Trevor Allen, Mohammad Bitarafan, Hugh Ramp, Clinton Potts, Xavier Rojas, Allison MacDonald, and John Davis

Doc ID: 234580 Received 18 Feb 2015; Accepted 24 Apr 2015; Posted 24 Apr 2015  View: PDF

Abstract: We report on the thermo-mechanical and thermal tuning properties of curved-mirror Fabry-Perot resonators, fabricated by the guided assembly of circular delamination buckles within a multilayer a-Si/SiO₂ stack. Analytical models for temperature dependence, effective spring constants, and mechanical mode frequencies are described and shown to be in good agreement with experimental results. The cavities exhibit mode volumes as small as ~10λ³, reflectance-limited finesse ~3x10³, and mechanical resonance frequencies in the MHz range. Monolithic cavity arrays of this type might be of interest for applications in sensing, cavity quantum electrodynamics, and optomechanics.

Comparative study of guided modes in hollow core Bragg fibers with binary and ternary photonic crystal claddings

Liang Shang, Zhixiang Huang, and Yan-Lin Liao

Doc ID: 234860 Received 18 Feb 2015; Accepted 24 Apr 2015; Posted 24 Apr 2015  View: PDF

Abstract: We comparatively investigate the modal properties of guided modes in hollow core Bragg fibers (HC-BFs) with the binary and ternary photonic crystal claddings by using a full-vector finite element method. The influences of structural changes from the binary photonic crystal (BPC) cladding to the ternary photonic crystal (TPC) cladding on the dispersion relations, confinement losses and modal field distributions of the lowest five guided modes are thoroughly discussed under different core diameters. The contrasts in bandwidths for the guided modes between both types of HC-BFs strongly depend on their distinct frequency cutoff characteristics. The bandwidth contrast for a given guided mode in large-core HC-BFs is different from that in small-core HC-BFs. The confinement losses of the fundamental HE11 mode in the TPC-based HC-BF are much lower than those in the BPC-based HC-BF, which is essentially attributed to the stronger modal-field confinement by the TPC cladding. The differences in the minimum confinement losses of the HE11 mode between both types of HC-BFs decrease with decreased core diameters. By contrast, the changes of cladding structures have very limited influence on the confinement loss of the TE01 mode in both the large-core and small-core HC-BFs. In addition, we explore the reasons behind the evolutions of the minimum loss contrast for the HE11 and TE01 modes between both types of HC-BFs with the core diameter, by quasi-quantificationally analyzing the influences of reflection characteristics of the transverse electric (TE) and transverse magnetic (TM) waves on the confinement loss.

Resonance Enhanced Absorption in a Graphene Monolayer Using Deep Metal Gratings

Zhuomin Zhang, Bo Zhao, and Junming Zhao

Doc ID: 235705 Received 05 Mar 2015; Accepted 23 Apr 2015; Posted 29 Apr 2015  View: PDF

Abstract: It has been demonstrated recently that metal gratings can significantly improve the near-infrared absorptance of graphene from 0.023 to nearly 0.70 due to the excitation of magnetic polaritons (MPs). The present study shows that the absorptance of graphene can be further enhanced to more than 0.80 by surface plasmon polaritons (SPPs) enabled by the grating. Meanwhile, graphene behaves as a sheet resistor that is able to boost the absorption when MPs or SPPs are excited without changing their resonance frequencies. Furthermore, MP-enhanced absorption is angular insensitive, whereas SPP-enhanced absorption depends strongly on the incidence angle. The effects of higher-order MPs as well as the grating geometry on the enhanced absorptance are also examined. Rigorous coupled-wave analysis (RCWA) is employed to calculate the radiative properties and power dissipation density in both the graphene and the metal grating. This study will facilitate the understanding of the coupling phenomena between graphene and nanostructures and may also benefit the design of next-generation graphene-based optical and optoelectronic devices.

Analysis and design of supercontinuum pulse generation in a single-mode optical fiber: erratum

Kunihiko Mori, Hidehiko Takara, and Satoki Kawanishi

Doc ID: 237649 Received 07 Apr 2015; Accepted 21 Apr 2015; Posted 23 Apr 2015  View: PDF

Abstract: We have corrected an erroneous definition of a normalized parameter that was introduced in our earlier paper [J. Opt. Soc. Am. B vol. 18, pp. 1780-1792] and resulting figures and parameters.

Detection of two-mode spatial quantum states of light by electro-optic integrated directional couplers

David Barral Raña, Mark Thompson, and Jesús Liñares

Doc ID: 235599 Received 03 Mar 2015; Accepted 21 Apr 2015; Posted 24 Apr 2015  View: PDF

Abstract: We study both manipulation and detection of two-mode spatial quantum states of light by means of a reconfigurable integrated device built in an electro-optical material in a Kolgelnik-Schmidt configuration, which provides higher error tolerance to fabrication defects and larger integration density than other current schemes. SU(2) transformations are implemented on guided spatial modes in such a way that reconstruction of both the optical field-strength quantum probability distribution, via spatial two-mode homodyne detection, and the full optical field-strength wavefunction, by means of weak values, are carried out. This approach can easily be extended to spatial N-mode input quantum states. Apart from its usefulness to characterize optical quantum states, it is also emphasized its application to the measurement of the so-called generalized quantum polarization.

A compact surface-plasmon-polariton dichroic splitter with high splitting ratio based on three cascaded grooves

Dalin Liu, Kun Li, Chih-Chun Ho, Fan Lu, Anshi Xu, and Bin Li

Doc ID: 233923 Received 04 Feb 2015; Accepted 20 Apr 2015; Posted 23 Apr 2015  View: PDF

Abstract: A compact surface-plasmon-polariton (SPP) dichroic splitter based on three cascaded nanogrooves of different dimensions is proposed. Photons normally incident on the dichroic splitting structure are converted to surface plasmons propagating to the left or right on the metal surface depending on the incident wavelength. A new operation principle is proposed to guide the structure design. Proof-of-principle demonstrations show that a remarkable property of high splitting ratios of 36.7 dB (right:left power flow contrast) at splitting wavelength of 600 nm and 42.4 dB (left:right power flow contrast) at wavelength of 800 nm is realized. The proposed design concept has very general applicability across other operating wavelengths, such as the communication bands (i.e. 1310 nm and 1550 nm).

On the transverse instability of solitons in nonlinear systems

Jisha Pannian, Mithun T, Augusto Rodrigues, and Porsezian Kuppuswamy

Doc ID: 235069 Received 20 Feb 2015; Accepted 18 Apr 2015; Posted 22 Apr 2015  View: PDF

Abstract: We study the transverse instability associated with higher dimensional nonlinear systems. For this, a cubic-quintic nonlinear system is considered wherein the coefficients of cubic and quintic terms are allowed to be either focusing or of de-focusing nature. It is found that a focusing-cubic and de-focusing quintic nonlinearity can suppress transverse instability growth rate. Addition of guiding potentials can also suppress the instability growth rate for all kinds of solitons with the same propagation constant.

Non-separated states from squeezed dark-state polaritons in electromagnetically-induced-transparency media

Ray-Kuang Lee, Chuang You-Lin, and Ite Yu

Doc ID: 225151 Received 17 Oct 2014; Accepted 17 Apr 2015; Posted 29 Apr 2015  View: PDF

Abstract: Within the frame of quantized dark-state polaritons in electromagnetically-induced-transparency media, noise fluctuations in the quadrature components are studied. Squeezed state transfer, quantum correlation, and noise entanglement between probe field and atomic polarization are demonstrated in single- and double-Λ configurations, respectively. Even though a larger degree of squeezing parameter in the continuous variable helps to establish stronger quantum correlations, inseparability criterion is satisfied only within a finite range of squeezing parameter. The results obtained in the present study may be useful for guiding experimental realization of quantum memory devices for possible applications in quantum information and computation.

Phase controlled sub-superluminal light propagation in double quantum wells

Mozhgan Momeni-Demne, Mostafa Sahrai, and Jafar Poursamad

Doc ID: 228446 Received 04 Dec 2014; Accepted 14 Apr 2015; Posted 22 Apr 2015  View: PDF

Abstract: Absorption and dispersion properties of an n-doped three-level semiconductor quantum well are investigated. The effect of coupling field intensity and the relative phase of applied fields on absorption and dispersion properties of a probe beam are then discussed. The required switching times for switching the group velocity of a weak probe field from subluminal to superluminal pulse propagation is also presented.

Saturable and inverse saturable absorption in multi-walled-carbon-nano-tubes-doped fast Sol-gel hybrid glasses

Raphi Dror, ZeeV Burshtein, Raz Gvishi, and Mariana Pokrass

Doc ID: 232480 Received 14 Jan 2015; Accepted 10 Apr 2015; Posted 10 Apr 2015  View: PDF

Abstract: Dynamics of saturable absorption and inverse saturable absorption of Multi walled carbon nano tubes (MWCNT)-doped fast Sol-gel hybrid glasses was studied by optical transmission of 532-nm laser beam pulses at two extreme conditions: 6-ns long temporally isolated single pulses up to 0.02 J/cm2, and a pulse train at different intensities in the range 0.72-10.7 kW/cm2 (quasi-CW illumination). The temporally isolated single pulses were analysed by the slow saturable absorber limit; The quasi-CW illumination at steady state was analysed by the fast inverse saturable absorber limit. A fresh, corrected solution to the rate equation was developed for the latter. The time dependence of reaching steady state absorption in the quasi-CW case was analysed by a numerical simulation of a state model. The single-pulse case analysis yields a ground-state density N=5.1×1015cm-3, a ground-state absorption cross-section σgs=5.5×10-15cm2 , and a first excited-state absorption cross-section σes1=3.6×10-15cm2. The quasi-CW case analysis is consistent with the occurrence of the MWCNT transition upon illumination into a highly absorbing/scattering state ("plasma" state). The analysis yields a ground-state concentration estimation N=3.2×1015cm-3, and a ground-state absorption cross-section σgs=6.3×10-15cm2. The "plasma" lower-state absorption/ scattering cross-section is σes2=2.3×10-14cm2. The light-intensity dependent transition rate between the first MWCNT excited-state and its "plasma" lower state followed the relation τ-1inc[s-1]=12.25exp(4×10-7I[W/cm2]); the transition rate between the lowest "plasma" state and the MWCNT ground-state, was also light-intensity dependent, following the relation τ-1[s-1]=3.5exp(2.54×10-7I[W/cm2]).

The effect of periodic modulation of the coupling ratios on the sensitivity of a CROW gyroscope

Kiarash Zamani Aghaie and Michel Digonnet

Doc ID: 225878 Received 28 Oct 2014; Accepted 10 Apr 2015; Posted 20 Apr 2015  View: PDF

Abstract: This paper presents numerical simulations of the sensitivity to rotation of a coupled resonant optical waveguide (CROW) gyroscope consisting of multiple rings with couplings periodically modulated strong and weak around the central ring. Two variations of this general configuration are considered, namely CROWs with either two separate input/output waveguides or a single input/output waveguide, and CROWs in which the rings are folded on top of each other. The single-waveguide folded CROW gyroscope is found to exhibit the highest sensitivity, and this maximum sensitivity is slightly lower than the maximum sensitivity of a single-resonator gyroscope.

Generating Hermite polynomial excited squeezed states by means of conditional measurements on a beam splitter

Hong-chun Yuan, Xue-xiang Xu, and Hong-yi Fan

Doc ID: 234066 Received 05 Feb 2015; Accepted 09 Apr 2015; Posted 14 Apr 2015  View: PDF

Abstract: A scheme for conditional generating a Hermite polynomial excited squeezed vacuum states (HESVS) is proposed. Injecting a two-mode squeezed vacuum state (TMSVS) into a beam splitter (BS) and counting the photons in one of the output channels, the conditional state in the other output channel is just a HESVS. To exhibit a number of nonclassical effects and non-Gaussianity, we mainly investigate the photon number distribution, sub-Poissonian distribution, quadrature component distribution, and quasi-probability distribution of the HPESVS. We find that its nonclassicality closely relates to the control parameter of the BS, the squeezed parameter of the TMSVS, and the photon number of conditional measurement. These further demonstrate that performing the conditional measurement on a BS is an effective approach to generate non-Gaussian state.

Post-compression of high energy terawatt-level femtosecond pulses and application to high order harmonic generation

Ondrej Hort, Eric Constant, Antoine Dubrouil, Eric MEVEL, Dominique Descamps, Amélie Cabasse, and Stephane Petit

Doc ID: 234143 Received 25 Feb 2015; Accepted 07 Apr 2015; Posted 10 Apr 2015  View: PDF

Abstract: We perform a post-compression of high energy pulses by using optical-field ionization of low pressure helium gas in a guided geometry. We apply this approach to a TW chirped-pulse-amplification based Ti:Sapphire laser chain and show that spectral broadening can be controlled both with the input pulse energy and gas pressure. Under optimized conditions, we generate 10 fs pulses at TW level directly under vacuum and demonstrate a high stability of the post compressed pulse duration. These high energy post-compressed pulses are thereafter used to perform high harmonic generation in a loose focusing geometry. The XUV beam is characterized both spatially and spectrally on a single shot basis and structured continuous XUV spectra are observed.

2D atom localization via phase-sensitive absorption-gain spectra in five-level hyper inverted-Y atomic systems

Wen-Xing Yang, Zhonghu Zhu, Aixi Chen, Shaopeng Liu, and Ray-Kuang Lee

Doc ID: 235152 Received 26 Feb 2015; Accepted 07 Apr 2015; Posted 10 Apr 2015  View: PDF

Abstract: A scheme for realizing two-dimensional (2D) atom localization in the sub-wavelength domain is proposed in a microwave-driven five-level hyper inverted-Y atomic system, in which the atom interacts with a weak probe field, two control fields together with two orthogonal standing-wave fields. Due to the spatially dependent atom-field interaction, the information about the position of the atom can be directly extracted out from the absorption and gain spectra of the weak probe field. It is found that the probe detuning, the intensities of two control fields and the relative phase of the driving fields can significantly improve the localization precision. Moreover, the maximal probability of finding the atom at an expected position in the sub-wavelength domain of the standing-wave field can reach unity via properly adjusting the system parameters.

Running electric field gratings for detection of coherent radiation

Germano Montemezzani, Virginie Coda, Massimo Alonzo, Peter Günter, and Mojca Jazbinsek

Doc ID: 235547 Received 03 Mar 2015; Accepted 07 Apr 2015; Posted 10 Apr 2015  View: PDF

Abstract: A technique for the room temperature electro-optic detection of coherent low-frequency radiation, typically in the far infrared or THz range, is proposed. It relies on a longitudinally running electric field grating probed by phase-matched Raman-Nath diffraction of a higher frequency wave. The expected probe wave diffracted intensity is background-free and is proportional to the desired signal intensity. As an example we present model calculations for the probing of monochromatic THz radiation using the organic crystal 4-N,N-dymethylamino-4'-N'-methyl-stilbazolium 2,4,6-trimethylbenzenesulfonate (DSTMS) as nonlinear optical sensor material, for which new measurements of the refractive index and absorption up to a frequency of 11 THz are presented.

Long baseline weak-thermal-light interferometry with noiseless linear amplification

WanSu Bao, XuBo Zou, Guang-can Guo, NingJuan Ruan, ZhiQiang Wu, and XuLing Lin

Doc ID: 220415 Received 04 Aug 2014; Accepted 07 Apr 2015; Posted 09 Apr 2015  View: PDF

Abstract: Long baseline weak-thermal-light interferometry is widely used for retrieving astronomical information from array of telescopes. However, optic loss in the baseline severely limits the length of baseline and thus limit the resolution of interferometries. In this paper, we consider the elimination of optic loss with quantum noiseless linear amplification(NLA). With a success probability of $1.98\times 10^{-3}$, one could implement a $100$ km long baseline interferometry, via $1550 \mathrm{nm}$ quantum communication. This shows the power quantum information technique and its application in astronomic interferometry. Finally, the comparison with recent entanglement-assisted method is also investigated.

Effects of engineering initial states and quantum interference near the edge of a photonic band gap on the entanglement

haozhen Li, shuangyuan xie, Xu Jingping, and Yaping Yang

Doc ID: 224912 Received 14 Oct 2014; Accepted 07 Apr 2015; Posted 09 Apr 2015  View: PDF

Abstract: The entanglement dynamics of a V-type three-level atom and its radiation field near the band edge of a photonic crystal is investigated. It is shown that the entanglement dynamics experiences periodic oscillation behavior with a constant amplitude, and can be enhanced or reduced by the quantum interference between the two atomic transitions. These properties depend strongly on the relative position between the upper levels and the band edge, and on the initial state of the atom. There is a special position at which the time evolution of the entanglement changes from oscillation to constant in the long time limits.

Strong circular dichroism of core-shell magnetoplasmonic nanoparticles

Aristi Christofi, Paris Varytis, N. Stefanou, and Nikolaos Papanikolaou

Doc ID: 237027 Received 26 Mar 2015; Accepted 03 Apr 2015; Posted 09 Apr 2015  View: PDF

Abstract: Composite magnetoplasmonic nanoparticles with a core-shell morphology exhibit intriguing optical properties and offer impressive opportunities for tailoring in a controllable manner the light-matter interaction at subwavelength dimensions. These properties are usually analyzed in the framework of the quasistatic approximation which, however, is often inadequate and thus a full electrodynamic treatment is required. In this respect, we developed a rigorous method for an accurate description of electromagnetic scattering by a gyrotropic sphere coated with a nongyrotropic concentric spherical shell, based on the full multipole expansion of the wave field. The method was applied on specific examples of core-shell cobalt-silver spherical nanoparticles, where the occurrence of strong circular dichroism induced by magnetoplasmonic interaction, which largely exceeds that of homogeneous noble metal nanoparticles in an external magnetic field, was found and the results were consistently interpreted.

Thermally induced beam distortions in laser ceramics at strong birefringence

Anton Vyatkin and Efim Khazanov

Doc ID: 232891 Received 20 Jan 2015; Accepted 03 Apr 2015; Posted 03 Apr 2015  View: PDF

Abstract: A new method of calculating quality parameters of a beam that has passed through laser ceramics whose grains are large compared to the wavelength at an arbitrary value of thermally induced birefringence has been developed. The intensity of a large-scale field in initial and orthogonal polarizations has been found. The results fully agree with the thermally induced distortions calculated by other methods. The intensity of a large-scale field was also obtained within the framework of the Rayleigh-Debye scattering theory for arbitrary size of ceramic granules.

Surface Plasmon Sorting and Engineered Dispersion Curves using Multilayer Doped Semiconductors

Young Uk Jung, ISroel Mandel, Igor Bendoym, Andrii Golovin, and David Crouse

Doc ID: 231112 Received 13 Jan 2015; Accepted 31 Mar 2015; Posted 03 Apr 2015  View: PDF

Abstract: A method to engineer complex shapes into the dispersion curves (DCs) of surface plasmon (SP) in flat multilayer structures composed of doped semiconductors is shown both analytically and numerically. It is shown that the shapes of SP DCs in multilayer structures can be engineered by controlling the not only the free electron density in each layer, as has been well described in past literature on the subject, but also by controlling the spatial profiles of the electromagnetic fields associated with surface plasmons. It is the ability to impart complex shapes in the SP DCs that is new and described in this paper, and not just raising or lowering the surface plasmon energies as a function of free electron concentration. DCs with stair-step shapes or dove-tails shapes are possible. In this work, a method to design structures that support SPs with DCs of arbitrary shapes of SP DCs is described. An analytical description of the design methodology is developed, and the resulting structures are numerically modeled using both continuous wave excitation and time-dependent pulsed excitations. Time domain studies of the creation and decay the SPs are performed, and the spatial sorting of the SPs are studied, and yield results in agrement with the predictions of the analytic model.

Far field narrowing in spatially modulated broad area edge-emitting semiconductor amplifiers

Mindaugas Radziunas, Ramon Herrero, Muriel Botey, and Kestutis Staliunas

Doc ID: 234035 Received 04 Feb 2015; Accepted 30 Mar 2015; Posted 03 Apr 2015  View: PDF

Abstract: We perform a detailed theoretical analysis of the far field narrowing in broad-area edge-emitting semiconductor amplifiers that are electrically injected through the contacts periodically modulated in both, longitudinal and transverse, directions. The beam propagation properties within the semiconductor amplifier are explored by a (1+2)-dimensional traveling wave model and its coupled mode approximation. Assuming a weak field regime, we analyze the impact of different parameters and modulation geometry on the narrowing of the principal far field component.

Hyperbolic Metamaterial Feasible for Fabrication with Direct Laser Writing Processes

Durdu Guney, Xu Zhang, and Sanjoy Debnath

Doc ID: 232762 Received 21 Jan 2015; Accepted 28 Mar 2015; Posted 03 Apr 2015  View: PDF

Abstract: Stimulated emission depletion microscopy inspired direct laser writing (STED-DLW) processes can offer diffraction-unlimited fabrication of 3D-structures, not possible with traditional electron-beam or optical lithography. We propose a hyperbolic metamaterial for fabrication with STED-DLW. First, we design meandering wire structures with three different magnetic dipoles which can be excited under different incidences of light. Then, based on effective parameters corresponding to normal incidence and lateral incidence, we find that the hyperbolic dispersion relation for five-layer structure appears between 15THz to 20 THz. Finally, we investigate the influence of imaginary parts of the effective parameters on the metamaterial dispersion. The proposed metamaterial structure has also potential for three-dimensionally isotropic permeability despite geometric anisotropy.

Bloch oscillations in an optical lattice generated by a laser source based on a fiber amplifier: decoherence effects due to amplified spontaneous emission

Saida GUELLATI-KHELIFA, Manuel ANDIA, Pierre CLADÉ, François BIRABEN, and Etienne WODEY

Doc ID: 231143 Received 19 Dec 2014; Accepted 26 Mar 2015; Posted 01 Apr 2015  View: PDF

Abstract: We present the development of a laser source generated by frequency doubling of a seed laser at 1560 nm using a periodically poled lithium niobate (PPLN) crystal. The seed laser passes through a 30 W fiber amplifier. The laser source at 780 nm is used to perform Bloch oscillations of ultra-cold atoms in an optical lattice. In this paper we investigate the decoherence effects induced by the amplified spontaneous emission (ASE) in the gain medium. We show that the ASE drastically reduces the efficiency of Bloch oscillations. We totally filter out the ASE around the D2-line using a heated rubidium vapor cell. We precisely determine the power spectral density of the ASE by measuring the fraction of atoms transferred from the hyperfine level F = 1 to F = 2, when the laser is switched on.

Experimental and theoretical study of passively Q-switched Nd:LuAG laser at 1.3 µm with V3+:YAG saturable absorber

Cheng Liu, Shengzhi Zhao, Guiqiu Li, Kejian Yang, Dechun Li, Tao Li, qiaowen chao, Tianli Feng, and Xintian Chen

Doc ID: 229202 Received 10 Dec 2014; Accepted 22 Mar 2015; Posted 03 Apr 2015  View: PDF

Abstract: We report the characteristics of a diode-pumped continuous-wave (CW) and passively Q-switched Nd:LuAG laser emitting 1.3 µm wavelength. A maximum average output power of 954 mW was obtained under CW operation, giving a slope efficiency of 14.7 %. With an V3+:YAG crystal wafer employed as saturable absorber, the passively Q-switched Nd:LuAG laser produced a minimum pulse duration of 17 ns under a repetition rate of 8 kHz, and a maximum single pulse energy of 18.9 µJ. A rate equation model is introduced to theoretically analyze the results obtained in the experiment, in which the Gaussian spatial distribution of the intracavity photon density and the longitudinal distribution of the photon density along the cavity axis are taken into account. The results of numerical calculations of the rate equations are consistent with the experimental results. The results indicated the Nd:LuAG crystal as promising gain medium for achieving short pulses with high energy at 1.3 µm

Wavelength dependence of reversible photodegradation of disperse orange 11 dye-doped PMMA thin films.

Benjamin Anderson, Mark Kuzyk, and Sheng-Ting Hung

Doc ID: 231934 Received 07 Jan 2015; Accepted 18 Mar 2015; Posted 01 Apr 2015  View: PDF

Abstract: Using transmittance imaging microscopy we measure the wavelength dependence of reversible photodegradation in disperse orange 11 (DO11) dye-doped (poly)methyl-methacrylate (PMMA). The reversible and irreversible inverse quantum efficiencies (IQEs) are found to be constant over the spectral region investigated, with the average reversible IQE being $\overline{B}_\alpha= 8.70 (\pm 0.38)\times 10^5$ and the average irreversible IQE being $\overline{B}_\epsilon= 1.396 (\pm 0.031)\times 10^8$. The large difference between the IQEs is consistent with the hypothesis that the irreversible species involves a dye-polymer complex. Additionally, we find that the recovery rate is independent of wavelength with a value of $\overline{\beta}=3.88(\pm 0.47) \times 10^{-3}$ min$^{-1}$. These results are consistent with the correlated chromophore domain model of reversible photodegradation.

On and off optical resonance dynamics of dielectric micro-cylinders under plane wave illumination

Ibrahim Mahariq and Hamza Kurt

Doc ID: 233418 Received 28 Jan 2015; Accepted 17 Mar 2015; Posted 01 Apr 2015  View: PDF

Abstract: We explore the on resonance and off resonance optical response of dielectric cylinders excited by normal incident plane waves. Both analytical method based on Mie theory and numerical method implemented with spectral element method are undertaken in the study. We demonstrate that whispering gallery mode characteristic of resonance behavior is strongly dependent on the refractive index and radius changes. Detuning of the either parameter deteriorates the resonance action and creates yet another exciting phenomenon known as photonic nano-jets. Sub-wavelength light focusing property can be associated with nano-jets and engineering the parameters yield strong field confinement and slowly diffracting beam propagation. The current work investigates the optical properties of the dielectric micro-cylinders at the close proximity of the resonance condition. Both strong field focusing associated with photonic nano-jet and enhanced field localization linked with the resonance condition are desired for photon manipulation scenarios in nano-photonics.

Breathing particles and clustering via synchronization

Svetlana Tatarkova

Doc ID: 233067 Received 21 Jan 2015; Accepted 17 Mar 2015; Posted 23 Apr 2015  View: PDF

Abstract: We report the first experimental observation of synchronization and clustering in an array of colloid microscopic particles confined in the extended optical trap. Under certain conditions initially random and incoherent fluctuations of the individual particles in the array go through an abrupt transition to a fully coherent state resulting in phase synchronization and clustering into a single giant oscillator. The factors triggering synchronization are identified. The interpretation of the results is given using the Kuramoto model. In addition the transverse snake-type instability is observed for clustered particles.

Bragg Holography in Active Semiconductor Microcavities

Hao Sun, David Nolte, Eric Harmon, and James Hyland

Doc ID: 232173 Received 26 Jan 2015; Accepted 20 Feb 2015; Posted 20 Apr 2015  View: PDF

Abstract: High-speed dynamic holography is studied numerically and experimentally in broad-area InGaAs/InP multiple-quantum-well asymmetric Fabry-Perot (ASFP) microcavities that have pumped gain gratings near the lasing threshold. Two numerical approximation methods are developed to predict Bragg diffraction effects in these active microcavities. The cavity Raman-Nath method assumes multipass Raman-Nath diffraction, while the Cavity Bragg method assumes an effective medium. Both methods predict that Raman-Nath diffraction in a micron thick cavity resonator can exhibit Bragg-like selectivity for angles near the Bragg angle. The angular and spectral selectivities are studied experimentally in optically-pumped free carrier gratings using a tunable 1.55 micron laser in a nondegenerate four-wave mixing configuration. The device operates at gigahertz speeds with transient diffraction efficiency near unity.

Optical nonlinearity enhancement in oblate semi-spheroid-shaped quantum dots coupled to wetting layer

Mohammadreza Shahzadeh and Mohammad Sabaeian

Doc ID: 224283 Received 06 Oct 2014; Accepted 17 Feb 2015; Posted 20 Apr 2015  View: PDF

Abstract: The authors report optical nonlinearity enhancement in oblate semi-spheroid-shaped quantum dots (QDs) coupled to wetting layer. To reach this result, two groups of InAs/GaAs QDs were examined. In group (A), the base length of semi-spheroid-shaped QDs was set to 14 nm and the height was changed from 3 to 14 nm. In group (B), the height was set to 4 nm and the base-length was increased from 10 to 25 nm. The energy eigenvalues, transition energies, transition dipole moments, oscillator strengths, and linear and nonlinear optical susceptibility of the two groups were compared. Nonlinear susceptibility of group (B) QDs was shown to be much more sensitive in both peak-position and value to size-changes, in contrast to group (A) QDs. Interestingly, a ~11.4 times increasing in real and imaginary parts of the third-order susceptibility was observed when the base-length of group (B) QDs was increased from 10 nm to 25 nm. Moreover, the third-order susceptibility of the most-stretched QDs of group (B), i.e. b=25nm, was shown to be ~4.6 times larger than the tallest QD of group (A), i.e. h=14 nm. Finally, the figure of merit showed ~3.38 times increasing with QD base length increasing from b=10 nm to b=25nm.

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