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Accepted papers to appear in an upcoming issue

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Tunable Raman gain in mid-IR waveguides

alfredo sanchez, Santiago Hernandez, Juan Bonetti, Pablo Fierens, and Diego Grosz

Doc ID: 305979 Received 05 Sep 2017; Accepted 16 Nov 2017; Posted 16 Nov 2017  View: PDF

Abstract: We demonstrate a tunable Raman gain which may find applications in a variety of fields, ranging from mid-IR fiber Raman lasers and supercontinuum generation to ultra-wideband slow-light Raman-based devices. In particular, by analyzing the interplay among Raman gain, dispersion and self-steeping (SE) in a full model of modulation instability (MI) in waveguides, we show that there exists a range of pump powers where the gain spectrum not only is dominated by the Raman contribution, but, most strikingly, it can be fine-tuned at will. We present analytical and numerical results, in excellent agreement, confirming this observation.

Transition between Kerr comb and stimulated Raman comb in a silica whispering gallery mode microcavity

Shun Fujii, Takumi Kato, Ryo Suzuki, Atsuhiro Hori, and Takasumi Tanabe

Doc ID: 306834 Received 19 Sep 2017; Accepted 16 Nov 2017; Posted 16 Nov 2017  View: PDF

Abstract: We theoretically and experimentally investigated the transition between modulation instability and Raman gain in a small silica microcavity with a large free-spectral range (FSR), which reveals that we can selectively switch from a four-wave mixing dominant state to a stimulated Raman scattering dominant state. Both the theoretical analysis and the experiment show that a Raman-dominant region is present between transitions of Kerr combs with different free-spectral range spacings. We can obtain a stable Kerrcomb and a stable Raman state selectively by changing the driving power, coupling between the cavity and the waveguide, and laser detuning. Such a controllable transition is achieved thanks to the presence of gain competition between modulation instability and Raman gain in silica whispering gallery mode microcavities.

Transmitting and Detecting THz Pulses Using Graphene and Metals Based Photoconductive Antennas

Ramin Emadi, Reza Safian, and Abolghasem Zeidaabadi Nezhad

Doc ID: 305797 Received 28 Aug 2017; Accepted 14 Nov 2017; Posted 15 Nov 2017  View: PDF

Abstract: In this paper, photoconductive antennas (PCAs) are designed using graphene ribbons (GRs) and metals at THz frequencies which both transmitting and detecting modes for PCAs are investigated. A graphene-based PCA (GPCA) can support surface plasmon polaritons (SPPs) at either THz or optical frequencies, whereas a metal-based PCA (MPCA) only support such waves at optical frequencies. Due to the 2D nature of graphene, its electronic and electromagnetic modeling significantly differ from 3D bulk metals, consequently some challenges appear when graphene is modeled in electronic and electromagnetic solvers. Hence, in this paper, the graphene's electronic and electromagnetic modeling are comprehensively examined. We show that through applying an electrostatic bias to a GR, its Fermi energy level can be shifted to an arbitrary value. This feature provides many striking advantages for a GPCA compared to a MPCA: supporting slow waves, reconfigurability, supporting SPPs at THz frequencies, mitigation of screening effects, enhancing radiated THz power. Although, supporting slow waves in a GR at THz frequencies through exciting a SPP results in a miniaturized structure for a GPCA, it causes the spatial dispersion for the GR's conductivity because the used photoconductor for a PCA usually has a high refractive index. As a consequence, a more complicated analysis is required for designing a GPCA. Moreover, by studying the fabrication challenges relating to a GR, some of them are considered during its modeling. Finally, through a coherent detection scheme, the radiated THz pulses are detected.

Band edge- and defect mode-induced emission from photonic crystal heterostructure cavity

Govind kumar and R. Vijaya

Doc ID: 303085 Received 25 Jul 2017; Accepted 13 Nov 2017; Posted 15 Nov 2017  View: PDF

Abstract: We numerically modeled and experimentally investigated a photonic crystal (PhC) heterostructure cavity with a three-dimensionally (3-D) ordered colloidal PhC made from Rhodamine-B dye-doped polymer colloids sandwiched between two identical dielectric multilayer stacks, for its influence on dye emission. In this cavity, we utilized the effect of overlap of the defect cavity mode of multilayer stack with the band edge of 3-D PhC to achieve enhancement and spectral narrowing in dye emission. The other defect modes which do not overlap with the band edge do not show this effect.

A less-dispersive specialty optical fiber with enhancedoperational bandgap for applications in the midinfrared

Somnath Ghosh, Prof. Abhijit Biswas, and Sayan Bhattacherjee

Doc ID: 306777 Received 08 Sep 2017; Accepted 12 Nov 2017; Posted 15 Nov 2017  View: PDF

Abstract: We propose a scheme to enhance the operational photonic bandwidth exploiting band-gap overlapping of same order or different orders through judiciously chosen aperiodic geometries of spatial dimension. To implement the scheme, we design a specialty optical fiber with hybrid chirped-cladding (HCC). Our designed fiber helps to merge fundamental band-gap with first higher order band-gap and thus provides an ultra-wide photonic bandwidth of 3 μm. The designed fiber structure also provides much flat dispersion profile in comparison to Conventional Periodic Cladding (CPC) fiber carrying the signature of zero dispersion at 2.7 μm. This opens up possibilities in mid-infrared wavelength regime for band-gap tunable fiber based devices. The proposed two materials all solid fiber geometry is consisted of thermally compatible low-loss chalcogenide glasses, GeAsSe and AsSe as low and high index respectively. The supported photonic bandwidth of the fiber covers entire material low-loss window of the chosen glasses. The efficient delivery of short moderate-energy pulses with significantly less distortion in temporal as well as spectral domain, and enhanced spectral broadening of specific high energy pulses under certain operating conditions are demonstrated through these specialty fibers.

Low-threshold terahertz-wave generation based on cavity phase-matched parametric process in a Fabry-Perot micro-resonator

Pengxiang Liu, Feng Qi, Weifan Li, yelong wang, zhaoyang liu, hongming wu, wei ning, Wei Shi, and Jian-Quan Yao

Doc ID: 305010 Received 28 Aug 2017; Accepted 11 Nov 2017; Posted 15 Nov 2017  View: PDF

Abstract: A configuration for optical pumped monochromatic terahertz (THz) source operated in high repetition rate is developed, which is based on resonant parametric process within a Fabry-Perot micro-cavity. Comprehensive analysis of the spectral selection, cavity phase matching, energy conversion dynamic and input-output characteristics are provided. Calculations are performed on Tm3+-doped fiber lasers pumped GaAs sheet. It is indicated that pump threshold can be scaled down by injection seeding of signal wave. Efficient THz-wave generation (mW-level average power) under relatively low pump peak power (65 kW) is predicted.

Tunneling-induced coherent perfect absorption in an optical cavity with coupled quantum wells

Yandong Peng, Zhongjian Zhang, Lu Xu, Aihong Yang, and Tingqi Ren

Doc ID: 308531 Received 03 Oct 2017; Accepted 10 Nov 2017; Posted 15 Nov 2017  View: PDF

Abstract: A scheme of tunneling-induced perfect absorption is proposed in an intracavity quantum-well (QW) system. In the linear case, the cavity transmission is found to be narrowed and weakened with respect to an empty cavity. In the nonlinear case, the resonant tunneling induces constructive interference for the nonlinear absorption, with the total absorption dramatically enhanced. For the cavity modes close to the QW resonant frequency, the cavity field can be absorbed completely, and the tunneling-induced perfect absorption (TPA) effect appears in the cavity transmission. The intensities of the control field and inter-well coupling broaden the TPA bandwidth, and the frequency detuning of the control field shifts the TPA window.

Generation and robustness of bipartite non-classicalcorrelations in two nonlinear microcavities coupledby an optical fiber

Abdel-Baset Mohamed and Hichem Eleuch

Doc ID: 301346 Received 30 Jun 2017; Accepted 09 Nov 2017; Posted 10 Nov 2017  View: PDF

Abstract: We explore the bipartite non-classical correlations of two quantum wellscoupled to two spatially separated micro-cavities. The micro-cavities are filled by linear optical media and linked by a single mode optical fiber. It is shown that the generation and robustness of the non-classical correlations which based on Wigner-Yanase skew information and Bell’s inequality are depend not only on the initial states, coupling strengths of the cavity-fiber and cavity-exciton, but also on the optical susceptibility as well as on the dissipation rates.

Atom and field squeezed output of three-level atom-laser surrounded by a Kerr medium in the electromagnetically induced transparency regime

M Tavassoly and E. Ghasemian

Doc ID: 298246 Received 20 Jun 2017; Accepted 09 Nov 2017; Posted 15 Nov 2017  View: PDF

Abstract: In this paper we investigate the squeezing properties of the output of an atom-laser which consists of an ensemble of three-level atoms in Bose Einstein condensate (BEC) state interacting with two quantized and classical laser fields in the presence of Kerr medium. Under electromagnetically induced transparency (EIT) regime and using the adiabatically elimination process, we represent the Hamiltonian of system in terms of angular momentum operators and then deduce the corresponding analytical state vector with the help of Dicke model. We pay our attention to the evaluation of atomic and field squeezing via numerical calculations. The results show that nonlinear sources in the system, i.e. "interatom collisions" and "Kerr medium" lead to squeezing of atoms and photons. In this respect, the squeezing values can be controlled by adjusting the strength of interatom collisions, Kerr medium as well as other involved parameters in the considered model. Also, collapse-revival phenomenon as a pure quantum feature can be observed in the behavior of atomic squeezing, while only irregular oscillations appeared in the field squeezing.

Advanced phase retrieval for dispersion scan: a comparative study

Esmerando Escoto, Tamas Nagy, Ayhan Tajalli, and Gunter Steinmeyer

Doc ID: 306458 Received 05 Sep 2017; Accepted 07 Nov 2017; Posted 08 Nov 2017  View: PDF

Abstract: Dispersion scan is a self-referenced measurement technique for ultrashort pulses. Similar to frequency-resolved optical gating, the dispersion scan technique records the dependence of nonlinearly generated spectra as a function of a parameter. For the two mentioned techniques, these parameters are the delay and the dispersion, respectively. While dispersion scan seems to offer a number of potential advantages over other characterization methods, in particular for measuring few-cycle pulses, retrieval of the spectral phase from the measured traces has so far mostly relied on the Nelder-Mead algorithm, which has a tendency of stagnation in a local minimum and may produce ghost satellites in the retrieval of pulses with complex spectra. We evaluate three different strategies to overcome these retrieval problems, namely regularization, use of a generalized-projections algorithm, and an evolutionary retrieval algorithm. While all these measures are found to improve the precision and convergence of dispersion scan retrieval, differential evolution is found to provide the best performance, enabling the near-perfect retrieval of the phase of complex supercontinuum pulses within less than ten seconds, even in the presence of strong detection noise and limited phase-matching bandwidth of the nonlinear process.

Fast vertical mode expansion method for the simulation of extraordinary terahertz field enhancement in an annular nanogap

Zhen Hu, Junshan Lin, Ya Yan Lu, and Sang-Hyun Oh

Doc ID: 305366 Received 22 Aug 2017; Accepted 07 Nov 2017; Posted 08 Nov 2017  View: PDF

Abstract: This paper is concerned with electromagnetic wave scattering of an annular nanogap in the terahertz regime. We present an efficient vertical mode expansion method (VMEM) to solve the scattering problem, and study the extraordinary optical transmission and field enhancement for the nanostructure with various configurations. The vertical mode expansion methodexpands the electromagnetic field in and outside the nanogap along the invariant direction by the one-dimensional modes, where the expansion coefficients satisfy scalar two-dimensional Helmholtz equations on the cross-sectional plane. The continuity conditions of electromagnetic fields on the vertical boundaries of neighboring regions are then employed to establish the linear system for the unknown coefficients. Based on the numerical simulations, we investigate the field enhancement in the nanogap. In particular, we investigate the nanostructure with a series of gap sizes and push the gap width limit to 1 nm in the numerical simulation. Both the normal and oblique incidence cases, the transverse electric (TE) and the transverse magnetic (TM) polarizations cases are considered.

Second Harmonic Generation of Second‐order Modes  in Thermally Poled Double‐anode Optical Fibers 

Lin Huang, Guobin Ren, Yixiao Gao, and Bofeng Zhu

Doc ID: 302504 Received 19 Jul 2017; Accepted 06 Nov 2017; Posted 08 Nov 2017  View: PDF

Abstract: Second harmonic generation (SHG) in double anode thermally poled fiber is numerically investigated. The poling process is investigated based on two-dimensional charge dynamics model. We show that SHG efficiencies of HE11, TM01 and HE21 mode are affected by χ(2) distribution in fiber core which can be deliberately deigned by varying poling parameters. Efficient TM01 SHG mode could be achieved in symmetry double anode poled fiber, which provides direct SHG of radial vector beams in compact all fiber based devices. HE11 and TM01 (or HE21) modes SHG at different wavelengths in a single poled fiber could also be available by using asymmetrical double anode poling, which can be potentially applied in two-wavelength or ultra-broadband second harmonic generation.

Energy transfer controlled by dynamical Stark shift in two-level dissipative systems

Andrei Ivanov

Doc ID: 304676 Received 11 Aug 2017; Accepted 05 Nov 2017; Posted 08 Nov 2017  View: PDF

Abstract: Interaction of an electron system with a strong electromagnetic wave leads to rearrangement both the electron and vibrational energy spectra of a dissipative system. For instance, the optically coupled electron levels become split in the conditions of the ac Stark effect that gives rise to appearance of the nonadiabatic coupling between the electron and vibrational motions. The nonadiabatic coupling exerts a substantial impact on the electron and phonon dynamics and must be taken into account to determine the system states. In this paper, the mechanism of energy transfer between the electron system and the phonon reservoir is presented. This mechanism is based on establishment of the coupling between the electron states dressed by the electromagnetic field and the vibrations of reservoir oscillators. In most general case, the photoinduced vibronic coupling is established by the interaction of electrons with the forced vibrations of reservoir oscillators under the action of rapid changing of the electron density with the Rabi frequency. However, if the resonance conditions for the optical phonon frequency and the transition frequency of electrons in the dressed state basis are satisfied, the vibronic coupling is due to the electron-phonon interaction. The photoinduced vibronic coupling results in appearance of the states that are doubly dressed by interaction, first time due to the electron-photon interaction, and second time due to the electron-vibrational interaction. Moreover, this coupling opens the way to control energy which can be transferred to (heating) or removed from (cooling) the phonon reservoir depending on the parameters of the electromagnetic pulse.

Reflectionless design of a nonmagnetic homogeneous optical waveguide coupler based on transformation optics

Hossein Eskandari, Amir Reza Attari, and Mohammad Saeed Majedi

Doc ID: 304001 Received 02 Aug 2017; Accepted 04 Nov 2017; Posted 08 Nov 2017  View: PDF

Abstract: In this paper, we propose a reflectionless design of an optical waveguide coupler that is nonmagnetic and homogeneous. The coupler is designed using the linear coordinate transformation of triangles from virtual space to physical space. The common problem of reflections from the boundaries of a nonmagnetic coupler is remedied by analytically specifying the common vertex of triangles in such a way that the Jacobian matrix determinant of the transformation becomes equal for all transformed triangles. The device performs ideal transmission without distorting the beam profile. We employ the effective medium theory to demonstrate the realizability of the device by using consecutive dielectric layers. Numerical finite element simulations confirm the functionality and the reflectionless property of the proposed designs.

Tunable hybrid Tamm-microcavity states

Pavel Pankin, Stepan Vetrov, and Ivan Timofeev

Doc ID: 307699 Received 25 Sep 2017; Accepted 03 Nov 2017; Posted 08 Nov 2017  View: PDF

Abstract: Spectral manifestations of hybrid Tamm-microcavity modes in a 1D photonic crystal bounded with a silver layer and containing a nematic liquid crystal microcavity layer have been studied using numericalsimulation. It is demonstrated that the hybrid modes can be effectively tuned owing to the high sensitivity of the liquid crystal to the temperature and external electric field variations. It is established thatthe effect of temperature on the transmission spectrum of the investigated structure is most pronouncedat the point of the phase transition of the liquid crystal to the isotropic state, where the refractive indexjump is observed.

Optical rectification of ultrashort laser pulses at the surface of conducting media

Sergey Uryupin and Stanislav Bezhanov

Doc ID: 307929 Received 25 Sep 2017; Accepted 03 Nov 2017; Posted 03 Nov 2017  View: PDF

Abstract: Optical rectification of ultrashort pulses is considered using Maxwell's equations and kinetic equation for electrons. When ponderomotive force plays key role in the excitation of slow nonlinear current we point out optimal conditions for low-frequency radiation generation. Accounting the effects of kinetic treatment of electron motion as well as the finite duration of the incident pulse are found to be necessary to build a correct theory of the THz radiation generation.

Graphene based mid-infrared biosensor

Zohreh Vafapour, Yaser Hajati, Morteza Hajati, and Hossain Ghahraloud

Doc ID: 308696 Received 06 Oct 2017; Accepted 02 Nov 2017; Posted 03 Nov 2017  View: PDF

Abstract: We proposed a new graphene based metamaterial biosensor to achieve tunable plasmon induced transparency in the mid-infrared (mid-IR) regime. The structure consists of a graphene sheet with three cut-out strips which has been located on a substrate. It is shown that the plasmonically induced transparency (PIT) can be realized by breaking symmetry of the structure in the normal incidence and also changing the polarization of the incident light in symmetric case. By optimizing the physical parameters of the antennas, an extremely strong optical sensing coefficient (about 99 percent) is observed in the mid-IR frequency range based on the PIT effect, which is much larger than that of related previous studies. More importantly, we observed a blue-shift in the transparency window trough increasing gate voltage of the graphene's chemical potential. The transparency window strongly depends on physical parameters of the substrate and filling material. Furthermore, it is found that the biosensing application of the proposed structure is highly dependent on inserting an ultra-thin buffer layer between the graphene and substrate layer leading to a tunable PIT in the mid-IR regime.

Theoretical study on the stimulated Brillouin scattering in a sub-wavelength anisotropic waveguide: Acousto-optical coupling coefficients and effects of transverse anisotropies

Xiao-Xing Su, Xiao-Shuang Li, Yue-Sheng Wang, and Heow Pueh Lee

Doc ID: 307523 Received 25 Sep 2017; Accepted 26 Oct 2017; Posted 27 Oct 2017  View: PDF

Abstract: A theoretical study on the stimulated Brillouin scattering (SBS) in a sub-wavelength anisotropic waveguide is conducted. The optical, photoelastic and mechanical anisotropies of the waveguide materials are all taken into account. First, the integral formulae for calculating the acousto-optical coupling coefficients (AOCCs) due to the photoelastic and moving interface effects in SBS are extended to an optically anisotropic waveguide. Then, with the extended formulae, the SBSs in an elliptical nanowire with strong transverse anisotropies are simulated. In the simulations, the elastic fields are computed with the inclusion of mechanical anisotropy. Observable effects of the strong transverse anisotropies are found in numerical results. Most notably, the SBS gains of some elastic modes are found to be very sensitive to the small misalignment between the waveguide axes and the principal material axes. Detailed physical interpretations of this interesting phenomenon are provided. This interesting phenomenon implies an attractive way for more sensitive tuning of the SBS gain without significantly changing the phononic frequency.

Substrate effects on the optical properties of metal gratings

Munehiro Nishida, Yutaka Kadoya, and Ryo Kikkawa

Doc ID: 303279 Received 25 Jul 2017; Accepted 26 Oct 2017; Posted 27 Oct 2017  View: PDF

Abstract: The transmission and near field enhancement spectra of thin metal gratings on a semiconductor designed for telecom band, ~1500 nm, were investigated theoretically. It was found that around the Rayleigh wavelength $\lambda_R$ the spectral peaks are pinned at $\lambda_R$, in marked contrast to the gratings in air where the peak wavelength is always longer than $\lambda_R$. We show that the difference is related to the absence/presence of the bound mode (BM) of the system, which corresponds to the Fabry-Perot (FP) resonance of the slit mode. In the thin gratings on a semiconductor, the BM disappears due to the large dielectric asymmetry above and below the grating, which results in different reflection phases for the slit mode at the grating-dielectric interfaces. It is also shown that the plasmonic band gap is large in gratings on semiconductors, enhancing the disappearance of the BM.

Enhanced transmission via cavity modes in gratings formed by subwavelength metallic cylinders

Diana Skigin and Marcelo Lester

Doc ID: 306073 Received 01 Sep 2017; Accepted 25 Oct 2017; Posted 27 Oct 2017  View: PDF

Abstract: In the last decades, special attention has been paid to the optical response of structures composed by periodic subwavelength slits in thin metallic sheets. Extraordinary transmission and evanescent-to-propagating conversion are two of the main effects that have been mostly investigated in these systems.In this paper we present an alternative way of enhancing the intensity diffracted by a grating through morphological electromagnetic resonances. Unlike nanoslit arrays, in this system the cavities are formed by periodically distributed chains of metallic subwavelength cylinders, which behave like walls that confine the fields and thus exhibit resonant behaviour. The set of cavities is illuminated by an evanescent wave generated by total internal reflection. We show that the resonant coupling of the cavity modes excited by the inhomogeneous wave produces enhanced transmission of up to 92% and also that the system has the ability of steering most of the transmitted intensity in a particular direction given by the diffraction orders. The results are compared with those obtained from a similar structure formed by periodically distributed perfectly conducting solid walls.

Generalized Range Migration Algorithm for SAR Image Reconstruction of Metasurface Antenna Measurements

Aaron Diebold, Laura Maria Pulido Mancera, Timothy Sleasman, Michael Boyarsky, Mohammadreza F. Imani, and David Smith

Doc ID: 304502 Received 16 Aug 2017; Accepted 22 Oct 2017; Posted 23 Oct 2017  View: PDF

Abstract: Waveguide-fed dynamic metasurface antennas (DMAs) can be used in a variety of synthetic aperture radar (SAR) modalities for microwave and millimeter wave imaging. The DMA consists of an electrically-large array of resonant, dynamically reconfigurable metamaterial radiators, each excited by the fields of a guided wave. A given metamaterial element can be modeled as a polarizable dipole, with polarizability that equates to a complex weighting factor in the context of antenna array calculations. The DMA produces a sequence of diverse radiation patterns as a function of the weights, which can be rapidly varied by external control. The unconventional radiation patterns of the DMA, however, introduce added computational complexity for traditional SAR processing algorithms. One SAR reconstruction approach that has successfully been adapted for the static (motionless) DMA is the range migration algorithm (RMA). Here, we extend the RMA to scenarios in which the DMA is physically translated in one or two dimensions, deriving the RMA for each case and providing experimental demonstrations using a fabricated microstrip-based DMA. Excellent reconstruction quality is observed in all cases, verifying the efficacy of the proposed algorithms and demonstrating the imaging capabilities of the DMA in the synthetic aperture context. The combination of the DMA platform with efficient reconstruction algorithms can find applications in fields such as earth observation, security screening, and autonomous vehicle navigation.

Stark effects in the ν₃ band of methane

Shoko OKUDA and Hiroyuki Sasada

Doc ID: 305656 Received 07 Sep 2017; Accepted 21 Oct 2017; Posted 24 Oct 2017  View: PDF

Abstract: Sub-Doppler resolution Stark-modulation spectra of 20 transitions in the ν₃ band of methane have been recorded using a difference-frequency-generation source referenced to an optical frequency comb with a frequency uncertainty of a few kilohertz. First-order Stark shifts in the vibrational excited (v₃ = 1) and ground states have been measured separately in the presence of an electric field up to 31 kV/cm. The observed spectra have been analyzed taking into account the mixing of the vibration-rotation wave functions due to high-order vibration-rotation interactions. The permanent electric dipole moment constants induced by the vibration, rotation, and Coriolis-type terms in the v₃ = 1 state, and that induced by rotation in the vibrational ground state are determined as $P^\mathrm{vib}=-16.82(7)$ mDebye, ${P^\mathrm{rot}}'=18.6(4)$ μDebye, $P^\mathrm{Cor}=10.4(17)$ μDebye, and ${P^\mathrm{rot}}'=24.47(12)$ μDebye.

Anisotropic polarization modulation for the production of arbitrary Poincaré beams

Shiyao Fu, Chunqing Gao, Tonglu Wang, Yanwang Zhai, and Ci Yin

Doc ID: 306353 Received 05 Sep 2017; Accepted 19 Oct 2017; Posted 08 Nov 2017  View: PDF

Abstract: In this paper, we show a universal scheme to produce arbitrary Poincaré beams of arbitrary positions (ρ, σ) on the surface of arbitrary order Poincaré sphere with high efficiency. The proposed arrangement consists of two liquid-crystal spatial light modulators (SLMs), a half wave plate (HWP) and a quarter wave plate. For the generated Poincaré beams, the longitude ρ is determined by the holograms on the second SLM while the latitude σ is controlled by the HWP. In the experiment, the generated Poincaré beams are analyzed through a polarizer, and a special parameter S3, showing good agreement with prediction.

The Transition Dynamics of Bright Soliton in a Binary Bose-Einstein Condensate

Li-Chen Zhao, Guo-Guo Xin, and Zhan-Ying Yang

Doc ID: 303626 Received 28 Jul 2017; Accepted 16 Oct 2017; Posted 16 Oct 2017  View: PDF

Abstract: Transition or tunneling dynamics have been studied widely in two-mode Bose-Einstein condensate systems with linear coupling effects. Nonlinear interaction between atoms would induce nonlinear Josephson oscillation which admits the oscillation form different from the classical Josephson oscillation. Similar extensions for Rosen-Zener tunneling and Landau-Zener tunneling also suggest that strong nonlinear strength would induce nonlinear type transition dynamics, in sharp contrast to the linear process. Interestingly, here we show a standard Josephson oscillation with constant linear coupling strength, no matter how strong the nonlinear interaction strength is. This character is in sharp contrast to the nonlinear Josephson oscillation reported before in nonlinear coupled systems. Through manipulating the linear coupling strength by RF field, we demonstrate that the Rosen-Zener transition particles, with an invariant distribution profile, can be managed well under exponential and periodic forms. Nonlinear interaction strength with the equal values are found to have no effects on the transition rate between atoms in the two components. The results are helpful for controllable population transfer between quantum states.

Unidirectional thermal radiation from SiC metasurface

Sandeep Inampudi, Jierong Cheng, Mohammad Mahdi Salary, and Hossein Mosallaei

Doc ID: 304494 Received 09 Aug 2017; Accepted 27 Sep 2017; Posted 01 Nov 2017  View: PDF

Abstract: Emission of thermal radiation from periodically patterned surfaces that support surface phonon polaritons has always been into two symmetric emission angles. This is because of the nature of randomness in the thermal spectrum of a hot body that symmetrically distributes the heat into counter propagating surface waves. Here we demonstrate design method of metasurfaces with unconventional unit cell dimension and internal structure to manipulate the thermal radiation into single specific emission angle. We utilize a combination of diffraction order engineering and numerical optimization techniques for the design process of an ultra thin metasurface to couple counter propagating surface waves into a single emission direction. In addition, we compute the near-field incoherent thermal emission intensity from the metasurface by combining the concepts of fluctuation dissipation theorem with solutions of Maxwell's equations based on rigorous coupled wave analysis and demonstrate unidirectional phase-less thermal radiation emission. The developed approach serves as a tool to design metasurfaces for manipulation of light sources with more complex nature than a plane wave.

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