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.
Effect of Coherence on All-Optical Signal Amplification by Supercontinuum Generation
Mikko Narhi, Gunter Steinmeyer, and Goëry Genty
Doc ID: 304587 Received 15 Aug 2017; Accepted 21 Nov 2017; Posted 22 Nov 2017 View: PDF
Abstract: A detailed study of all-optical signal amplification is presented, which exploits the extreme sensitivity of supercontinuum generation to input power fluctuations. As useful signal amplification relies on determinism and a correlation between input and output signal, the question naturally arises whether such conditions can be maintained in the presence of a modulation instability, which is usually expected to strongly reduce the coherence of supercontinuum pulse trains. To this end, the effect of coherence on the amplification is investigated for 200 fs input pulses across the full bandwidth of the supercontinuum. This study clearly shows that even in the case of partial coherence, the amplification mechanism based on soliton-dispersive wave coupling can be maintained, allowing for the amplification of weakly modulated signals by factors in excess of 40 dB in the normal dispersion regime.
Ultra-high birefringent nonlinear silicon-core microfiber with two zero-dispersion wavelengths
Xiaoying He, chong li, Zonghai Hu, and xia guo
Doc ID: 304692 Received 11 Aug 2017; Accepted 21 Nov 2017; Posted 22 Nov 2017 View: PDF
Abstract: A simple silicon-core microfiber has been proposed to simultaneously achieve ultrahigh birefringence order of 10-1, large nonlinear coefficient, and two zero-dispersion wavelengths. The full-vector finite-element method with circular perfectly matched layer boundary is used to simulate the properties of our proposed microfiber. It is suitable to achieve two zero-dispersion wavelengths of ~1280 and ~1817 nm for x-polarized HE11 mode and of ~1293 and ~1695 nm for y-polarized HE11 mode, when the major and minor diameter are respectively ~ 1.05 and ~ 0.315 μm, and the radius of the silicon core is about 135.35 nm. Meanwhile, the nonlinear coefficients of two non-degenerated HE11 modes at the wavelength of 1550nm are ~ 17.42 and ~ 33.77 W-1m-1 respectively, and the maximum birefringence is about ~ 0.24 at 1550nm wavelength. Therefore, our proposed silicon-core microfiber exhibits excellent polarization and nonlinearity performance, which enables it to be used for polarization maintaining nonlinear signal processing, such as supercontinuum spectrum generation, parametric amplification, optical nonlinear sensor and so on.
Optical steering of mutual capacitance in nematic liquid crystal cell
Filip Sala and Marzena Sala-Tefelska
Doc ID: 306583 Received 07 Sep 2017; Accepted 21 Nov 2017; Posted 22 Nov 2017 View: PDF
Abstract: In this study a variable capacitor made of Nematic Liquid Crystal cell is proposed and analyzed theoretically. The mutual capacitance is steered with an optical beam of a Gaussian shape launched into the cell. The optical field changes the orientation of the molecules and affects the capacitance. By using Frank-Oseen elastic theory the molecular reorientation is simulated. The influence of various parameters on capacitance such as, beam width, anchoring condition, externally applied voltage, beam power and launching position is presented. For instance, the maximum tuning range is achieved for wide beams and the molecules initially aligned close to the propagation axis. It is also proved that launching position, especially for narrow beams, has limited influence on capacitance. The proposed component can be used, for instance, in optical power meters, as a feedback in laser or light emitting diode systems or just as a variable capacitor in optoelectronic circuits. One of the advantages of this device is that the beam passes through the element, so steering of the capacitance or measuring the parameters of the beam can be realized in-system, without splitting the beam. Moreover, due to the low thickness of the liquid crystal layer the attenuation is very low.
Circular edge states in photonic crystals with a Dirac node
Doc ID: 303525 Received 22 Aug 2017; Accepted 18 Nov 2017; Posted 20 Nov 2017 View: PDF
Abstract: Edge states are studied for the two-dimensional Dirac equation in a circular geometry. The properties of the two-component electromagnetic field are discussed in terms of the three-component polarization field, which can form a vortex structure near the Dirac nodewith a vorticity changing with the sign of the Dirac mass. The Berry curvature of the polarization field is related to the Berry curvature of the Dirac spinor state. This quantity is sensitive to a change of boundary conditions. In particular, it vanishes for a geometry with a single boundary but not for a geometry with two boundaries.This effect is robust against the creation of a step-like edge inside the sample.
Dual-channel narrowband polarization absorber with high field enhancement and refractive index sensitivity based on nanorod array
Wenli Cui, Yuzhang Liang, qiao Wang, Yun Liu, Lixia Li, Mengdi Lu, ZHIDONG ZHANG, Jean-François Masson, and Wei Peng
Doc ID: 304288 Received 08 Aug 2017; Accepted 17 Nov 2017; Posted 20 Nov 2017 View: PDF
Abstract: In this paper, we present a dual-channel narrowband polarization absorber based on a metal-dielectric-metal (MDM) structure, which consists of a top metallic nanorod array, a metal substrate, and an ultrathin middle dielectric spacer. The proposed structure can achieve high absorptance above 96% in a wider angular range of incidence around ±20° at two remarkable absorption peaks for transverse magnetic(TM) polarization under normal incidence. Most significantly, the extremely highly confined enhancement of electromagnetic fields between Au film and nanorods has been observed by employing numerical simulation based on a finite element method, which is up to 110 times compared to incident electric field. The underlying physics mechanism of a strong gap plasmon resonance is analyzed, and it is primarily attributed to the simultaneous excitation of multiple localized electric dipole and magnetic dipole resonance modes in this film-coupled nanorods system. Additionally, we investigate the dependence of dual resonance peaks on structural parameters, as well as their sensitivities to the refractive index of the media surrounding the nanorods. The functions of wavelength modulation and intensity modulation are shown. This structure has great potential in various measurement and analyzing applications such as near-perfect absorption device, plasmonic refractive index bio-sensor and surface-enhanced Raman spectroscopy.
Radiation pressure on a two-level atom: an exact analytical approach
Lionel Podlecki, Rohan Glover, John Martin, and Thierry Bastin
Doc ID: 307695 Received 25 Sep 2017; Accepted 17 Nov 2017; Posted 20 Nov 2017 View: PDF
Abstract: The mechanical action of light on atoms is nowadays a tool used ubiquitously in cold atom physics. In the semiclassical regime where the atomic motion is treated classically, the computation of the mean force acting on a two-level atom requires in the most general case numerical approaches. Here we show that this problem can be tackled in a pure analytical way. We provide an analytical yet simple expression of the mean force that holds in the most general case where the atom is simultaneously exposed to an arbitrary number of lasers with arbitrary intensities, wave vectors, and phases. This yields a novel tool for engineering the mechanical action of light on single atoms.
Theory of optically controlled anisotropic polariton transport in semiconductor double microcavities
M Luk, Przemyslaw Lewandowski, Nai-Hang Kwong, Emmanuel Baudin, Ombline Lafont, JEROME TIGNON, Pui-tang Leung, Chris K. P. Chan, Martin Babilon, Stefan Schumacher, and Rolf Binder
Doc ID: 305708 Received 28 Aug 2017; Accepted 17 Nov 2017; Posted 22 Nov 2017 View: PDF
Abstract: Exciton polaritons in semiconductor microcavities exhibit many fundamental physical effects, with some of them amenable to being controlled by external fields. The polariton transport is affected by the polaritonic spin-orbit interaction, which is caused by the splitting of transverse-electric and transverse-magnetic (TE-TM) modes. This is the basis for a polaritonic Hall effect, called optical spin Hall effect (OSHE), which is related to the formation of spin/polarization textures in momentum space, determining anisotropic ballistic transport, as well as related textures in real space. Owing to Coulombic interactions between the excitonic components of the polaritons, optical excitation of polaritons can affect the OSHE. We present a theoretical analysis of the OSHE and its optical control in semiconductor double microcavities, i.e.\ two optically coupled cavities, which are particularly well suited for the creation of polaritonic reservoirs that affect the spin-texture-forming polaritons. The theory is formulated in terms of a set of double-cavity spinor-polariton Gross-Pitaevskii equations. Numerical solutions feature, among other things, a controlled rotation of the spin texture in momentum space. The theory also allows for an identification of the effective magnetic field component that determines the optical control in phenomenological pseudo-spin models in terms of exciton interactions and the polariton density in the second lower polariton branch.
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, Ayhan Tajalli, Tamas Nagy, 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
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.
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.
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.