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Accepted papers to appear in an upcoming issue

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Raman Modes Non-classicality through Entangled Photons Coupling to Plasmonic Modes

Ahmad SalmanOgli

Doc ID: 327805 Received 05 Apr 2018; Accepted 17 Aug 2018; Posted 17 Aug 2018  View: PDF

Abstract: In this article, non-classical properties of Raman modes are investigated. The original goal, actually, is to identify how and by which method we can induce non-classicality in Raman modes. We introduce a plasmonic system in which Raman dye molecules are buried between two shells of the plasmonic materials similar to onion-like core/shell nanoparticle. This system is excited by the entangled photons, followed by analyzing its dynamics of motion using the Heisenberg-Langevin equations by which the time evolution of the signal-idler mode and Raman modes are derived. Interestingly, the entangled photons are coupled to the plasmonic modes which are used to improve the non-classicality. It is shown that the exciting system with the entangled photons lead to inducing the non-classicality in Raman modes and entanglement between them. This behavior is attributed to the non-classicality of input modes that is coupled to the Raman modes considering the correlation between the incident wave frequency and Raman modes frequency. Notably, these quantum properties are dramatically affected by the environment temperature and Raman molecules location around the plasmonic nanoparticles. Modelling results demonstrate that the temperature increasing has a drastic effect on system dynamics. Moreover, it is found that the entanglement between modes in system surely is affected by the coupling between the incident modes and plasmonic modes generated by the core/shell nanoparticles. Finally, as an important result, it is revealed that the Raman modes such as stoke and anti-stoke modes show a revival behavior, which is a quantum phenomenon.

Phase-sensitive heterodyne detection of two-mode squeezed light without noise penalty

Boya Xie, peng yang, and Sheng Feng

Doc ID: 330628 Received 30 Apr 2018; Accepted 17 Aug 2018; Posted 17 Aug 2018  View: PDF

Abstract: Squeezed states of light can be detected for precision measurements with a heterodyne detector by use of a bichromatic field as the local oscillator, due to the phase sensitive nature of the device. However, divergence consists in the theoretical description of the quantum noise performance of this detector. Two existing theoretical models are briefly reviewed, with one model predicting a 3 dB quantum-noise floor change in detection of two-mode squeezed light if the local oscillator is replaced by a monochromatic one, whereas the other model foretelling the same noise floor no matter which local oscillator is used. An experiment on heterodyne detection of two-mode squeezed light is carried out to put the two models under test. No significant difference in the noise floor level is observed between the two detectors, showing the noiseless property of both detectors. This work should be of importance for the understanding of noise origin in optical detection and of great interest in practical application for squeezing-enhanced audio band gravitational-wave signal searching.

Line parameters of 12CH4 around 2.008 μm studied by tunable diode laser spectroscopy with long-path White cell

HONGLIANG MA, SHENLONG ZHA, XUEYUAN CAI, GUANNAN LIN, and Zhensong Cao

Doc ID: 331721 Received 14 May 2018; Accepted 17 Aug 2018; Posted 17 Aug 2018  View: PDF

Abstract: The absorption spectrum of 12CH4 at 2.008 μm has been recorded at 296 K, by using a high-resolution tunable diode laser absorption spectrometer combined with a long-path multi-pass White cell. The line positions, intensities and self-broadening coefficients for thirty-two transitions of the lower part of the Tetradecad in the 4975-4985 cm-1 spectral range of 12CH4 have been measured. To our knowledge, no experimental information has been obtained for the self-broadening coefficients of these lines before. Comparisons of the line parameters determined in present work with those from HITRAN2016 line lists are given.

Optical response induced by bound states in the continuum in arrays of dielectric spheres

Evgeny Bulgakov and Dmitrii Maksimov

Doc ID: 334535 Received 06 Jun 2018; Accepted 16 Aug 2018; Posted 17 Aug 2018  View: PDF

Abstract: We consider optical response induced by bound states in the continuum (BICs) in arrays of dielectric spheres.By combining quasi-mode expansion technique with coupled mode theory (CMT) we put forward a theory of the optical responseby high-Q resonance surrounding BICs in momentum space. The central result areanalytical expressions for the CMT parameters, which can be easily calculated from the eigenfrequencies and eigenvectorsof the interaction matrix of the scattering systems. The results obtained are verified in comparison against exactnumerical solutions to demonstrate that the CMT approximation is capable of reproducing Fano features in the spectral vicinity ofthe BIC. Based on the quasi-mode expansion technique we derived the asymptotic scaling law for the CMT parameters in the vicinity ofthe $\Gamma$-point. It is rigourously demonstrated that the line width in the CMT approximation exhibits different asymptotic behaviordepending on the symmetry of the BIC.

Optomechanical Entanglement of Remote Microwave Cavities

Brian Clader and Samuel Hedemann

Doc ID: 328425 Received 18 Apr 2018; Accepted 16 Aug 2018; Posted 17 Aug 2018  View: PDF

Abstract: We examine the entanglement properties of a system that represents two driven microwave cavities each optomechanically coupled to two separate driven optical cavities which are connected by a single-mode optical fiber. The results suggest that it may be possible to achieve near-maximal entanglement of the microwave cavities, thus allowing a teleportation scheme to enable interactions for hybrid quantum computing of superconducting qubits with optical interconnects.

Reconfigurable Coupler Based Metallic Photonic Crystal Lens and Nematic Liquid Crystal

Nihal Areed, Marwa Hussien, and Salah Obayya

Doc ID: 331561 Received 11 May 2018; Accepted 15 Aug 2018; Posted 17 Aug 2018  View: PDF

Abstract: In this paper, a new design for lens built around 2D metallic photonic crystal (PhC) platform with negative refractive index is proposed and simulated. The proposed lens has been composed of sliver layer with a triangular array of circular air holes. Three dimensional (3D) geometric study performed with the aid of two dimensions (2D) finite element method (FEM) results in focusing the light rays with intensity and FWHM of 10.5 and 1.7 µm; respectively. The suggested lens has been employed to couple efficiently the light from a planar waveguide with a large spot size area into another PhC waveguide with a sub-wavelength spot size area. Additionally, filling the drilled holes in the proposed metallic PhC lens with nematic liquid crystal (NLC) allows obtaining reconfigurable PhC lens with significant wave FWHM shaping with extinction ratios of about 8 dB. The proposed reconfigurable lens has been employed for coupling two different waveguides with different coupling ratios by controlling the biasing state of the NLC layer.

Spectral discrete diffraction with non-Hermitian coupling

Shaolin Ke, Qingjie Liu, Dong Zhao, and Weiwei Liu

Doc ID: 331698 Received 14 May 2018; Accepted 15 Aug 2018; Posted 17 Aug 2018  View: PDF

Abstract: We investigate the frequency conversion in a waveguide by dynamically modulating the real and imaginary parts of permittivity, namely, the complex modulation. A single frequency of incident light could convert into many discrete frequencies with equivalent intervals, which is analogous to discrete diffraction in spatial waveguide arrays. We develop a coupled mode theory to analyze the frequency conversion process and show the complex modulation results in complex-valued coupling coefficient between adjacent frequency channels. The coupling strength can be flexibly tuned by controlling the modulation amplitudes. Moreover, the complex coupling becomes asymmetric with increasing the modulation phase difference between the real and imaginary parts of permittivity. The capability to control the complex coupling leads to new features in discrete diffraction in the frequency dimension, including the unidirectional transport and equalization of light intensities at different channels. The study may find interesting application in frequency comb generators and frequency controllers.

Design of homogeneous-material cloak and illusion devices for active and passive scatterer with multi-folded transformation optics

Hamza Madni, NAILA ASLAM, Shahid Iqbal, Shuo Liu, and Wei Xiang Jiang

Doc ID: 332519 Received 29 May 2018; Accepted 15 Aug 2018; Posted 17 Aug 2018  View: PDF

Abstract: By adopting multi-folded linear transformation optics method and its corresponding numerical techniques, we introduce a method to design open cloak that has windows to exchange matter with the outer world. Compared with conventional remote cloaks based on inhomogeneous materials, in this paper, the inhomogeneity of materials is removed and the cloaking functionality can be achieved by anisotropic properties. Based on this, open-illusion devices for both active and passive scatterers have been investigated to make any radiators and objects look like another pre-defined radiator and object, respectively. The proposed devices have perfect performance with object-independent feature especially to moving objects. The proposed devices will open up possibilities and useful for practical implementations of cloak and illusion optics technologies that were recently developed. OCIS codes: ( 0.3205) Invisibility cloaks; (160.3918) Metamaterials

An ab-initio design of a realistic Fabry-Pérot cavity for accurate refractive index determination of fluids

Juan Guillermo Munguia Fernandez, Vicenta Sanchez, and Chumin Wang

Doc ID: 325420 Received 06 Mar 2018; Accepted 11 Aug 2018; Posted 13 Aug 2018  View: PDF

Abstract: Fabry-Pérot cavities provide a simple and precise alternative to measure the refractive index of liquids and gases, whose performance is very sensitive to the quality of its dielectric multilayer mirrors. In this article, a combined ab-initio and transfer-matrix study is carried out for a realistic Fabry-Pérot microcavity made of TiO₂/SiO₂ including interface atomic diffusions and possible layer thickness variations. The refractive indexes obtained from the density functional theory are used as the input of cavity transmittance calculations. The quality of such Fabry-Pérot cavity is monitored by the finesse and the full width at half maximum (FWHM) of its main resonant peaks. The results confirm the exponential decrease of FWHM with the number of layers and then an exponential growth of the finesse. An analytical solution for the optical transmittance of few-layer cavities is also presented. Furthermore, the results reveal a non-uniform shift of the resonant peaks, due to the presence of a finite layer interface width or a layer thickness fluctuation, despite the absence of peak broadening. Finally, measurements of the refractive index of air, CO₂ and ethanol by using this ab-initio designed realistic Fabry-Pérot microcavity are analyzed in detail.

Impact of ordering of gold nanohole arrays on refractive index sensing

Padmanabhan Viswanath and Brindhu Malani

Doc ID: 332617 Received 29 May 2018; Accepted 11 Aug 2018; Posted 13 Aug 2018  View: PDF

Abstract: Hexagonally ordered gold nanohole arrays of various hole size having fixed thickness are fabricated using colloidal lithography. The degree of ordering of gold nanohole arrays were obtained using pair correlation function and bond-orientation order parameter. Reflectance studies show both localized surface plasmon resonance and propagating surface plasmon polaritons. These optical responses are found to be dependent on the hole size variations and their ordering. The spectral resolution of each plasmonicresonance dip is evaluated by full height/full width at half-maximum. It improves with the long-range ordering and higher bond-orientational order parameter. Based on order quantification and optical response, the optimal sample is chosen for refractive index sensing yielding sensitivity of 470.49 nm/RIU and figure of merit of 14.42.

Controlling optical field collapse by elliptical symmetry hybrid polarization structure

Dan Wang, Yue Pan, Jia-Qi Lv, Ping-Ping Li, Gui-Geng Liu, Mengqiang Cai, Yongnan Li, Chenghou Tu, and Hui-Tian Wang

Doc ID: 332334 Received 24 May 2018; Accepted 10 Aug 2018; Posted 14 Aug 2018  View: PDF

Abstract: Engineering the diversity of spatial structure of polarization states offers a new approach to produce the controllable and designable filament patterns. Here we predict theoretically and demonstrate experimentally the novel collapsing behaviors of the optical fields by using the elliptical symmetry hybrid polarization structure in a self-focusing Kerr medium. The results reveal that the distribution of the hybrid polarization states, the spin angular momentum (SAM) gradient, and the collapsing patterns could be manipulated by changing the eccentricity, the topological charge and the initial phase of the optical field. Owing to the synergy of the hybrid polarization states and its spatial symmetry, the collapsing behaviors are controllable and have the robust feature insensitive to the random noise. Our idea may offer an alternative route to produce the controllable and robust multiple filamentation in other nonlinear systems, thereby facilitating the development of additional surprising applications.

Frequency locking of multiple lasers to an optical cavity

Luis Gonzáles, Eduardo Gomez Garcia, Ma. Nieves Arias, and Vahideh Abediyeh

Doc ID: 332979 Received 08 Jun 2018; Accepted 10 Aug 2018; Posted 14 Aug 2018  View: PDF

Abstract: We demonstrate the locking of multiple lasers to an ultra low expansion cavity using a single fiber modulator. We use the modulator to lock the frequency of one of the sidebands to the cavity resonance using an extension of the Pound-Drever-Hall technique. The frequency of the carrier can be tuned by changing the sidebands separation. We distinguish the signal coming from different lasers by their modulation frequency in the demodulation. The scheme is scalable to a large number of lasers without requiring extra optical components.

Using excited states and degeneracies to enhance the electric polarizability and first hyperpolarizability

Ethan Crowell and Mark Kuzyk

Doc ID: 332169 Received 21 May 2018; Accepted 10 Aug 2018; Posted 13 Aug 2018  View: PDF

Abstract: We investigate the efficacy of boosting the nonlinear-optical response by using novel systems such as those in an excited state or with a degenerate ground state. By applying the Three Level Ansatz (TLA) and using the Thomas-Reiche-Kuhn (TRK) sum rules as constraints, we find the electric polarizability and first hyperpolarizability of excited state systems to be bounded, but larger than those derived for a system in the ground state. It is shown that a system with a degenerate ground state can have divergent polarizabilities and that such divergences are real and not relics of a pathology in the perturbation theory. Furthermore, we demonstrate that these divergences only occur on time scales short compared to the relaxation time of the population difference to an equilibrium value. Such systems provide a way to get ultra-large nonlinear optical response. We discuss examples of huge enhancements in molecules and double quantum dots using a double quantum well as a model.

Ping-Pong protocol based on orbital angularmomentum of light

Farnaz Farman, Sara Tofighi, and Alireza Bahrampour

Doc ID: 328803 Received 23 Apr 2018; Accepted 10 Aug 2018; Posted 10 Aug 2018  View: PDF

Abstract: ‎Orbital angular momentum (OAM) is one of the photon's degrees of freedom in infinite-dimensional Hilbert space‎. ‎In this paper‎, ‎we use this photon property to propose a modified version of the deterministic two-way quantum key protocol, known as Ping-Pong protocol, based on OAM of light‎. ‎The advantage of the protocol is, it doesn't require Bell measurement for decoding the information being transmitted‎, ‎which makes the protocol more flexible and feasible for practical applications‎. ‎We propose an implementation setup and show how the channel capacity of the protocol ‏‎can‎ be increased easily‎. ‎The security of the protocol is analyzed and the probability of detecting Eve in general incoherent attack is obtained‎.

Vector solitons and dispersive waves in birefringent optical fibers

Govind Agrawal and Prannay Balla

Doc ID: 327403 Received 02 Apr 2018; Accepted 09 Aug 2018; Posted 09 Aug 2018  View: PDF

Abstract: We develop a general formalism for investigating the evolution of arbitrarily polarized short pulses inside a birefringent optical fiber. We use it to study numerically the formation of a dispersive wave inside fibers exhibiting medium to high birefringence, when a short optical pulse is launched such that it propagates as a vector soliton. We also investigate the polarization evolution of both the vector soliton and dispersive wave generated by it. The results show that while the polarization of dispersive wave is controlled by linear birefringence of the fiber, polarization of the vector soliton is affected considerably by the nonlinear birefringence. The coupled nonlinear equations that we solve include both the Raman and the Kerr nonlinearities. Moreover, they include the cross-polarization Raman terms that couple the orthogonally polarized components of the vector soliton. Polarization of the vector soliton is found to be affected considerably by the Raman nonlinearity in the case of medium birefringence.

Self-oscillation in the Maxwell-Bloch Equations

Jie Wu, Hideo Mabuchi, and Michael Armen

Doc ID: 331618 Received 15 May 2018; Accepted 08 Aug 2018; Posted 09 Aug 2018  View: PDF

Abstract: We elucidated the mechanism of supercritical Hopf bifurcation in the semi-classical Maxwell-Bloch equations for cavity quantum electrodynamics (QED) by formulating the atom-field interaction as a feedback control loop. It turns out that the existence of self-oscillatory states is a rather unexpected manifestation of the atomic pseudospin precession dynamics born out of the atom-field interaction governed by the driven Jaynes-Cummings Hamiltonian.

Quantum optical diode based on Lyapunov control in a superconducting system

Yexiong Zeng, Tesfay Gebremariam, Ming-Song Ding, and Chong Li

Doc ID: 336185 Received 27 Jun 2018; Accepted 08 Aug 2018; Posted 09 Aug 2018  View: PDF

Abstract: In this paper, we show how to use Lyapunov control theory to realize the unidirectional transmission of photons. We investigate quantum diode in a two-cavity system that is consists of two coplanar waveguide resonators connected by a superconducting quantum interference device, where the coupling strength can be adjusted by a magnetic flux. We utilize the Lyapunov control theory to design the shape of the coupling coefficient so that the dynamic evolution of the system can be effectively controlled. Moreover, we select the more stable and feasible control scheme by comparing and analyzing two control methods. Our scheme can obtain a high efficiency of photon transmission in the presence of quantum noise, without the need to construct strong nonlinear interactions, thus greatly reduces the difficulty of the experiment.

SU(1,1) parity and strong violations of a Bell inequality by entangled Barut-Girardello coherent states

Edwin Hach, Richard Birrittella Jr., Paul Alsing, and Christopher Gerry

Doc ID: 337677 Received 02 Jul 2018; Accepted 08 Aug 2018; Posted 09 Aug 2018  View: PDF

Abstract: We study the violations of the Bell-Clauser-Horne-Shimony-Holt inequality for entangled SU(1,1) Barut-Girardello coherent states. As in a previous paper where violations of the inequality were studied for entangled SU(1,1) coherent states of the Perelomov form (E.E. Hach, III, et al., Phys. Rev. A. 93, 042104 (2016)), we choose as our observable the SU(1,1) parity operator, though here we discuss the physical meaning of the operator for single-mode and two-mode bosonic realizations of the su(1,1) Lie algebra. We show that the SU(1,1) parity operator is not the same as the usual photon-number parity operator but rather is a form of higher-order photon-number parity. Distant observers Alice and Bob perform on each of their subsystems non-compact SU(1,1) transformations characterized by hyperbolic angles, followed by measurements of the SU(1,1) parity operators. We find strong violations of the inequality over a wide range of parameters, the violations attainable being stronger than those that can be obtained by the entangled Perelomov SU(1,1) entangled state.

Enhanced nonlinear optical response of core-shell graphene-wrapped spherical nanoparticles

tayebeh naseri and mohsen balaei

Doc ID: 335743 Received 20 Jun 2018; Accepted 07 Aug 2018; Posted 07 Aug 2018  View: PDF

Abstract: We study the nonlinear optical response of graphene in nanostructures. The spherical nanoparticle coated with a monolayer of graphene displays enhanced optical Kerr nonlinearity and consequently optical bistability and multistability in a broad range of incident optical intensity. This optical bistability significantly appertains on the geometry of the shell-coated nanoparticle, the fractional volume of the metallic core as well as the core genre and Fermi energy of graphene. In particular, Fermi energy could also affect the optical bistability and induce switching from optical bistability to optical multistability. Due to the importance of core-shell nanoparticles, this model may find potential applications in optical bistable devices such as all-optical switches, optical transistors, and memories.

PT-Symmetric Coherent Perfect Absorber withGraphene

Mustafa Sarısaman and Murat Tas

Doc ID: 326992 Received 12 Apr 2018; Accepted 07 Aug 2018; Posted 08 Aug 2018  View: PDF

Abstract: We investigate PT -symmetric coherent perfect absorbers (CPAs) in the TE mode solution of a linear homogeneous optical system surrounded by graphene sheets. It is revealed that presence of graphene sheets play a role to adjust the enhancement of absorption in a CPA. We derive exact analytic expressions, and work through their possible impacts on lasing threshold and CPA conditions. We point out roles of each parameter governing optical system with graphene and show that optimal conditions of these parameters give rise to enhancement and possible experimental realization of a CPA laser. Presence of graphene leads the required gain amount to reduce considerably based on its chemical potential and temperature. We obtain that relation between system parameters decides the measure of CPA condition. We find out that graphene features contributing to resonance effect in graphene sheets are rather preferable to build a better CPA.

An efficient marching treatment for optical propagation in the waveguide with a discontinuous interface

Jianxin Zhu and Shijie Zhao

Doc ID: 332817 Received 31 May 2018; Accepted 07 Aug 2018; Posted 08 Aug 2018  View: PDF

Abstract: In this paper, an efficient numerical method is developed for solving a two-dimensional Helmholtz equation in the optical waveguide with a discontinuous interface. The optical propagation is solved by an improved marching scheme based on the Dirichlet-to-Neumann (DtN) map. A local orthogonal transformation is applied to flatten the curved interface, and the discontinuous point of the interface brings the waveguide discontinuity problem and misalignment of the transformed fields, which are solved by the transformations of marching operators. The numerical results show that our method is feasible and can avoid the error caused by the discontinuity.

Shaping and amplification of wavelength-tunable mid-infrared femtosecond pulses generated by intra-pulse difference frequency mixing with spectral focusing

Fumihiko Kannari, Yuki Yamaguchi, Ryohei Hida, Takakazu Suzuki, Fumihiro Isa, Kenta Yoshikiyo, Leo Fujii, and Hirofumi Nemoto

Doc ID: 336249 Received 27 Jun 2018; Accepted 07 Aug 2018; Posted 08 Aug 2018  View: PDF

Abstract: Versatile mid-infrared (MIR) laser pulses ranging from 2 to 2.5 μm are generated from a single supercontinuum (SC) pulse by intra-pulse difference frequency mixing (DFM) with a spectral focusing scheme (SF-DFM). By controlling the spectral phase of the SC pulse with a 4f-pulse shaper utilizing a liquid crystal spatial light modulator (LC-SLM), SF-DFM enables to vary the center wavelength, the bandwidth, and the pulse shape of MIR laser pulses, which are amplified by OPA using a PPLN crystal. In principle, these MIR pulses exhibit an intrinsically stable carrier-envelope phase (CEP) since they are generated from the intra-pulse DFM process.

Design of metal-dielectric resonant cavity thin film structures using the effective reflectance index method

Andrew Sarangan

Doc ID: 324798 Received 29 May 2018; Accepted 07 Aug 2018; Posted 07 Aug 2018  View: PDF

Abstract: A mathematical design process for the resonant condition of metal-dielectric-metal cavity designs is presented in this paper. The technique is based on theeffective reflectance index of multilayer thin films, and the refractive indices of the films are self-consistently included. The scaling behavior of metal-dielectric structures as a function of wavelength for different metals is analyzed, from the visible to near-infrared spectrum. The maximum achievable peak transmission, as well as the design tradeoffs between sheet resistance, resonant wavelength and the choice of metals have been calculated.

Nonlinear Fourier transform using multi-stage perturbation technique for fiber-optic systems

Elham Bidaki and Shiva Kumar

Doc ID: 330911 Received 04 May 2018; Accepted 07 Aug 2018; Posted 07 Aug 2018  View: PDF

Abstract: Recently the application of nonlinear Fourier transform (NFT) for fiber optic communication system has drawn significantly attention. In this system, the Kerr effect in fibers can no longer be considered as impairments and hence,channel capacity can be significantly enhanced. One of the challenges in real time implementation of the NFT based system is the computational complexity of the NFT. In this paper, we develop a novel nonlinear discrete Fourier transform based on multi-stage perturbation technique. When the signal energy is small, the NFT can be evaluated by the single stage second or third order perturbation methods. We develop a novel multi-stage perturbation technique which provides reasonably accurate results even when the signal energy is not small. The number of stages required depends on the signal energy and desired accuracy. Modifying the fast Fourier transform algorithm, the computational cost of the NFT based on multi-stage perturbation technique is found to be 𝑶 𝑲𝑵𝒍𝒐𝒈𝟐 𝑵/𝑲 where 𝑵 is the number of signal samples and 𝑲 is the number of stages. An advantage of the proposed approach is that the computation can be split into FFTs of smaller lengths which can be processed on K parallel processors. The computational cost per processor is 𝑶 𝑵𝒍𝒐𝒈𝟐 𝑵/𝑲 . In the proposed approach, the NFT is realized by the cascade of linear discrete Fourier transforms, which provides a promising way to implement the NFT in optical domain.

Launching swarms of microsatellites using a 100kW average power pulsed laser

Claude Phipps, Christophe Bonnal, Frederic Masson, and Pietro Musumeci

Doc ID: 334160 Received 01 Jun 2018; Accepted 06 Aug 2018; Posted 07 Aug 2018  View: PDF

Abstract: Transferring small payloads from Earth to low Earth orbit (LEO) and to interplanetary space using laser ablation propulsion is a new application of pulsed laser ablation propulsion which offers parameters not available with chemical propulsion. In earlier work, we showed how to use a 1MW average power pulsed laser to launch a 25kg satellite from LEO to a Mars Hohmann transfer orbit in 18 minutes. Here, we discuss a lower power application, which can achieve the same result and also cheaply and rapidly launch swarms of microsatellites into geosynchronous orbit (GEO) for communication, Earth observation and observation of assets in GEO. The result will be a network of satellites with different functions that is robust to failures. Laser propulsion offers orbit/launch mass ratio m/M impossible with chemical rockets, and low launch cost/kg. The main purpose in this paper is to illustrate satellite launch with repetitive pulse lasers at realistic laser average power levels. The benchmark laser has 80ps pulsewidth, 5kJ pulse energy, 355nm wavelength (3rd Nd harmonic) and 20Hz pulse repetition rate, using the “L’ADROIT” laser station design. In order to minimize laser power, we employ 8 loops of steadily increasing apogee, propelled at perigee by a L’ADROIT laser in LEO, followed by a circularization “burn” at apogee using a second L’ADROIT in GEO with similar laser power. We estimate final mf /M ratio for these maneuvers to be 43-53%%, delivering 10.8kg into a Mars Hofmann transfer orbit and 13.2kg to GEO. The ablated mass is contained in a spherical shell surrounding the satellite payload composed of a mixture of metal powder and polyoxymethylene (POM). The mixture is tailored to the mission to give a matched specific impulse Isp and momentum coupling coefficient Cm. For the GEO insertion, the ablation shell splits and is reëntered after one orbit by a final “burn” from the GEO laser.

Quantum Fluctuations Inside a Microcavity with a Pair of Quantum Wells: Linear Regime

Houcem Jabri and Hichem Eleuch

Doc ID: 331874 Received 16 May 2018; Accepted 06 Aug 2018; Posted 08 Aug 2018  View: PDF

Abstract: Quantum fluctuations of a system formed by two quantum wells inside a microcavity are investigated. Noise spectrum and the autocorrelation function are analyzed and analytical expressions are derived. It is shown here, that the noises are equally balanced over direct and indirect exciton thermal bathes. The double quantum wells system induces more fluctuations compared to the system formed by a single quantum well inside a microcavity. Unlike the latter system, the autocorrelation function of the Terahertz cavity depends on the exciton thermal bath populations. It turns out that the photon detection probability is affected by the coupling with the indirect exciton thermal bath.

Efficiently Modeling the Noise Performance of Short-Pulse Lasers with a Computational Implementation of Dynamical Methods

Shaokang Wang, Curtis Menyuk, and Thomas Carruthers

Doc ID: 336190 Received 27 Jun 2018; Accepted 05 Aug 2018; Posted 13 Aug 2018  View: PDF

Abstract: Lowering the output noise of short pulse lasers has been a long-standing effort for decades. Modeling the noise performance plays a crucial role in isolating the noise sources and reducing them. Modeling to date has either used analytical or semi-analytical implementation of dynamical methods or Monte Carlo simulations. The former approach is too simplified to accurately assess the noise performance in real laser systems, while the latter approach is too computationally slow to optimize the performance as parameters vary over a wide range. Here, we describe a computational implementation of dynamical methods that allows us to determine the noise performance of a passively modelocked laser within minutes on a desktop computer and is faster than Monte Carlo methods by a factor on the order of 1000 . We applythis method to characterize a laser that is locked using a fast saturable absorber—for example, a fiber-based nonlinear polarization rotation device—and a laser that is locked using a slow saturable absorber—for example, a semiconductor saturable absorbing mirror.

Cavity-enhanced microwave electric field measurement using Rydberg atoms

Yandong Peng, Jinling Wang, Aihong Yang, Zhengmao Jia, Dehua Li, and Bing Chen

Doc ID: 332818 Received 29 May 2018; Accepted 04 Aug 2018; Posted 07 Aug 2018  View: PDF

Abstract: An enhanced measurement of microwave electric (MW E) field is proposed using intracavity Rydberg atoms. Based on electromagnetically induced transparency (EIT), the intracavity atomic system exhibits two EIT windows, resulting in two narrow peaks in the cavity transmission. The peak-to-peak distance is sensitive to MW fields, which can be used to probe MW E-field strength. Simulation results show that the detectable minimum strength of MW fields is more than ten times smaller than that of without a cavity. Due to cavity coupling, the transmission spectrum is much narrowed, which improves the measurement resolution substantially. The numerical results show that the spectrum resolution is increased by more than twenty times. Furthermore, the cavity-enhanced measurement scheme seems to be robust against the changes in the control field strength and shows a broadband tunability.

Laser ablated Ti velocity distribution dynamics

William Bauer and Glen Perram

Doc ID: 332880 Received 31 May 2018; Accepted 02 Aug 2018; Posted 07 Aug 2018  View: PDF

Abstract: Emissive plumes resulting from pulsed ablation of titanium targets have been observed using a gated ICCD camera to characterize the evolution of velocity distributions as the plume expands into vacuum, Ar, and He backgrounds. The gated imagery allows for the collection of time-of-flight spectra with highly sampled spatial resolution and the characterization of the velocity changing collisional dynamics. Multi-modal, shifted Maxwell-Boltzmann distributions with flow speeds of u > 0.1 cm/µs are adequate only for expansion into vacuum. Neutral Ti time of flight data clearly indicate three distinct distributions, with fastest component consistent with the ionized Ti velocity distribution and maximum kinetic energies exceeding 20 eV. Expansion into He and Ar are clearly non-Maxwellian, with the highest velocity groups suffering collisions in the shock front. Leading edge velocities of ~1.6 cm/μs decrease more rapidly for Ar at rates of ~30% per cm, consistent with momentum conservation. Expansion into He maintains the appearance of the vacuum distribution at low velocities but shows a decrease in the leading-edge velocity and an enhancement of the intensity of the highest-velocity groups at farther target distances. Determination of velocity distributions from time of flight data is complicated by translation-to-electronic excitation rates, intraplume collisional dynamics, and non-hydrodynamic conditions.

Emission Spectra of Hexagonal Zinc Oxide Microrods Due to Resonant Modes

Yu-Da Chen, Trong Ngo, Yia-Chung Chang, Dai-Jie Lin, and Hsu-Cheng Hsu

Doc ID: 326174 Received 16 Mar 2018; Accepted 02 Aug 2018; Posted 02 Aug 2018  View: PDF

Abstract: Experimental observation and theoretical analysis of the whispering gallery mode (WGM) related emission spectra of ZnO microrods with hexagonal cross-section are reported. ZnO microrods of various sizes are fabricated and their individual geometric information (including the inner radius, edge profile modification, and tilt angle) are characterized via scanning electron microscopy (SEM). The Photoluminescence (PL) spectra in visible range (with energies between 1.77eV and 2.76eV) are compared with theoretical simulation based on Green function calculation within a nearly complete set of basis functions. WGM resonance peaks for TE and TM modes of five different sizes of microrods are analyzed. By using the SEM determined geometry with slight adjustment, we obtain realistic simulation of the line shapes of the emission spectra, which agree well with experimental observation. To gain better understanding of the WGM resonance modes, we also calculate the WGM resonance profile of ZnO microrods with cylindrical cross-section for both TE and TM modes for comparison.

Normal mode splitting in an optomechanical system: Effects of Coulomb and parametric interactions

Ali Asghari Nejad, Hassan Ranjbar Askari, and Hamid Reza Baghshahi

Doc ID: 326365 Received 21 Mar 2018; Accepted 02 Aug 2018; Posted 02 Aug 2018  View: PDF

Abstract: In this paper, we consider a hybrid optomechanical system, in which a cavity with a one-end oscillating mirror interacts with an optical parametric amplifier (OPA) and another mechanical resonator. Interaction between oscillating mirror of the cavity and the second mechanical resonator is assumed to be a Coulomb interaction. We show that, the presence of OPA and the Coulomb interactions result in observing normal mode splitting in the output spectra of the cavity and displacement spectrum of the movable mirror. Also, it will be shown that, with the increase of the gain coefficient of OPA and the strength of the Coulomb interaction we see an intensified mode splitting in the spectra of the system.

Multi-zone single-shot femtosecond laser ablation of silica glass at variable multi-photon ionization paths

Sergey Kudryashov, Pavel Danilov, Andrey Ionin, and Startseva Kate

Doc ID: 334264 Received 04 Jun 2018; Accepted 02 Aug 2018; Posted 08 Aug 2018  View: PDF

Abstract: Tightly focused 515-nm, 220-fs laser pulses produce on silica glass surface single-shot micro-craters with their diameters, revealing in certain intensity ranges different multi-photon – one-, two- and four-photon – absorption mechanisms with the increasing integer number of photons. The corresponding inter-band transitions involve the electronic density-of states tails in the bandgap and main valence/conduction bands, respectively. In these intensity ranges the depth of the single-shot craters can be fitted, accounting for the derived multi-photon absorption mechanisms, to evaluate the corresponding multi-photon absorption coefficients. The intensity-dependent variation of multi-photon absorption mechanisms provides the three-zone ablation both across the surface and into the bulk of the silica glass.

Subwavelength focusing in visible light band by a Fibonacci photonic quasi-crystal plano-concave lens

Weijie Zhang, Wei Tan, Qifan Yang, Ting Zhou, and Jianjun Liu

Doc ID: 331572 Received 14 May 2018; Accepted 02 Aug 2018; Posted 09 Aug 2018  View: PDF

Abstract: A one-dimensional photonic quasi-crystal (1D PQC) plano-concave lens is proposed. The simulation results show that, there is a certain relationship between the focusing band and its photonic band structure: within the frequency range that in the passband between the first large bandgap and the second large bandgap, from a certain frequency in the passband to the left edge of the second large bandgap, the plano-concave lens can achieve subwavelength focusing. The influence of the change of refractive index of material on the focusing characteristics of the lens is studied, and subwavelength focusing in visible light band is achieved using the common dielectric materials. The results are expected to provide a reference for the design and application of the 1D PQC plano-concave lenses.

Swift-Hohenberg Soliton Explosions

Sofia Latas, Mario F.S. Ferreira, and Margarida Facao

Doc ID: 331191 Received 08 May 2018; Accepted 01 Aug 2018; Posted 02 Aug 2018  View: PDF

Abstract: New soliton explosions in the context of the Swift-Hohenberg equation (CSHE) have been found and analyzed in both temporal and spectral domains. In particular, very irregular explosions, with huge temporal extensions were found. The impact of the filter profile and the higher order effects (HOEs), namely intrapulse Raman scattering (IRS) and third order dispersion (TOD) is analyzed. A comparison between the CSHE and complex-Ginzburg Landau equation (CGLE) soliton explosions is performed. Simulations show that a proper combination of the filter profile and HOEs allows a fixed-shape pulse propagation for HOEs parameter values lower than for the CGLE case.

Shaping VCSEL Mode Profiles with Antiresonant Oxide Island for Improved Single-Mode Emission

Marta Więckowska, Tomasz Czyszanowski, Guilhem Almuneau, and Maciej Dems

Doc ID: 333035 Received 31 May 2018; Accepted 31 Jul 2018; Posted 02 Aug 2018  View: PDF

Abstract: Single-mode emission is one of the most significant problems in vertical-cavity surface-emitting lasers (VCSELs). To solve it, we propose to embed an antiresonant oxide island inside the VCSEL cavity using a novel planar oxidation technique. This oxide island has a strong impact on the shape of the lateral mode profiles and affects the values of photon lifetimes associated with each mode. In this work, we investigate the physical origin of this impact and determine the dimensions of the oxide island that provide the strongest modal discrimination.

Enhancement of surface plasmon resonances on the nonlinear optical properties in an elliptical quantum dot

Kangxian Guo and Tao Yang

Doc ID: 331462 Received 11 May 2018; Accepted 29 Jul 2018; Posted 02 Aug 2018  View: PDF

Abstract: In this paper, the nonlinear optical properties in an elliptical semiconduct quantum dot(SQD) have been calculated theoretically. By using the effective mass approximation and compact-density-matrix method, the third-harmonic generation(THG), optical absorption coefficients(OA) and refractive index changes(RICs) have been obtained with or without surface plasmon resonances(SPRs). It is found that the enhancement of SPRs has an important effect on the nonlinear optical properties. At the same time, these properties are also affected intensively by the different radius of metallic nanoparticle(MNP).

Supercontinuum Generation in Heavy-Metal Oxide Glass Based Suspended-Core Photonic Crystal Fibers

AMAR GHOSH, Mariusz Klimczak, Ryszard Buczynski, John Dudley, and Thibaut Sylvestre

Doc ID: 334532 Received 06 Jun 2018; Accepted 27 Jul 2018; Posted 07 Aug 2018  View: PDF

Abstract: In this paper we investigate supercontinuum (SC) generation in several suspended-core soft-glass photonic crystal fibers (PCFs) pumped by an optical parametric oscillator (OPO) tunable around 1550 nm. The fibers were drawn from lead-bismuth-gallium-cadmium-oxide glass (PBG81) featuring a wide transmission window from 0.5-2.7 µm and a high nonlinear refractive index up to 4.3 × 10-19 m2/W. They have been specifically designed with a microscale suspended hexagonal core for efficient supercontinuum generation around 1550 nm. We experimentally demonstrate two SC spectra spanning from 1.07-2.31 µm and 0.89-2.46 µm by pumping two PCFs in both normal and anomalous dispersion regimes at 1550 nm and 1580 nm, respectively. We also numerically model the group velocity dispersion curves for these fibers from their scanning electron microscope images. SC generation results are in good agreement with numerical simulations based on the generalized nonlinear Schrödinger equation including the pump frequency chirp.

Nonlinear dynamics and propagation of four components with different polarizations and frequencies in a single optical pulse by using a five-level atomic system

Miao Wang, Chao Hang, and Guoxiang Huang

Doc ID: 332024 Received 17 May 2018; Accepted 25 Jul 2018; Posted 27 Jul 2018  View: PDF

Abstract: We investigate the nonlinear dynamics and propagation of four components with different circular polarization states and frequencies in a single optical pulse, occurring in a resonant M-type five-level atomic system via electromagnetically induced transparency. We show that these four components in the system are coupled to each other due to the symmetry of the level configuration. We demonstrate that, for long probe pulses, self-trapped polarization states with a trapped phase can be obtained. In addition, a polarization rotor can be realized through a polarization instability, which can be working at a very low light level and may have a practical application. For short probe pulses, four-component optical solitons can be generated in the system, which have very slow propagating velocity and very low generation power. The results reported here may have potential applications in optical information processing and transmission.

Quantum evolution speed in the finite-temperature bosonic environment

Jun-Qing Cheng, Guo-Qing Zhang, and Jing-Bo Xu

Doc ID: 335725 Received 21 Jun 2018; Accepted 23 Jul 2018; Posted 27 Jul 2018  View: PDF

Abstract: We investigate the quantum evolution speed of a qubit in two kinds of finite-temperature environments. For the first bosonic bath with Ohmic-like spectrum, the high temperature not only leads to the speed-up but also speed-down processes in the weak-coupling regime, which is different from the strong-coupling case where only exhibits speed-up process. Furthermore, we realize the controllable and stationary quantum evolution speed by applying the bang-bang pulse. For the second nonlinear bath, we study the quantum evolution speed by resorting to the hierarchical equations of motion method beyond the Born-Markov approximation. It is shown that the quantum evolution speed can be decelerated by the rise of temperature in the strong-coupling regime which is an anomalous phenomenon and contrary to the common recognition that quantum evolution speed always increases with the temperature.

Experimental radiative lifetimes, branching fractions, and oscillator strengths of some levels in Y I

Qiu Li, Qi Yu, Xinghao Wang, Yang Gao, Wang Qian, Yimin Gong, and Zhenwen Dai

Doc ID: 330808 Received 03 May 2018; Accepted 19 Jul 2018; Posted 02 Aug 2018  View: PDF

Abstract: Radiative lifetimes of 17 levels in Y I were measured with time-resolved laser-induced fluorescence technique. Among them 13 levels are reported for the first time, to our knowledge. Branching fractions for 72 lines related to these Y I levels were determined based on the spectra by the Fourier transform spectrometer at the National Solar Observatory (NSO) on Kitt Peak, USA (http://diglib.nso.edu/ftp.html). By combining the results of lifetimes and branching ratios, the transition probabilities and oscillator strengths of these lines were calculated.

Anomalous zero-group-velocity photonic bondingstates with local chirality

Moïse Sotto, Kapil Debnath, Ali Khokhar, Isao Tomita, David Thomson, and Shin-ichi Saito

Doc ID: 330361 Received 27 Apr 2018; Accepted 16 Jul 2018; Posted 18 Jul 2018  View: PDF

Abstract: Photonic Crystal Waveguides (PCWs) are promising candidates for the basic building blocks of quantum information processing because they support circular polarization points that can unbalance the directionality of an integrated quantum emitter (QE). Nevertheless, the Purcell effect at circular polarization points saturates near the band-edge, the preferred region for Quantum ElectroDynamics (QED). Consequently, chirality and ultra-strong light-matter interaction are difficult to combine.Here, we detract from the vicinity of the band-edge, and couple modes with different parities by breaking the mirror symmetry.Using three-dimensional finite-difference time domain method (3D-FDTD), simulated bandstructures of the implemented Photonic Bonding States (PBS) display single-mode anomalous zero-group-velocity (ZGV) points far from the band edge. The electric field patterns of these points feature circular polarization points at high field intensity regions where a QE would acquire uni-directional emission behavior.Fabricated devices in Silicon (Si) slabs demonstrate the predicted coupling energy between the modes and the signature of single-mode anomalous ZGV points.This method to engineer PBS in PCWs paves the way for outperforming chiral light-matter experiment on-chip.

Modal gain equalization of 18 modes using single-trench ring-core EDFA

Ankita Gaur and Vipul Rastogi

Doc ID: 324869 Received 26 Feb 2018; Accepted 13 Jul 2018; Posted 18 Jul 2018  View: PDF

Abstract: Few mode erbium doped fiber amplifier (FMEDFA) is a key component of few mode fiber (FMF) based optical communication system to allow the simultaneous amplification of all signal mode groups. This article proposes the single-trench ring-core FMEDFA for gain equalization of five signal mode groups LP01, LP11, LP21, LP31 and LP41. The proposed fiber with ring-core Er^+3 doping and fundamental pumping is used to study the gains and differential modal gains (DMGs) of signal mode groups. In this study, we have shown that introduction of trench increases the modal confinement of higher mode groups and decreases that of lower mode groups in ring region (or doped region) slightly. This helps in controlling the DMG and also increases the effective index difference ∆neff between the adjacent modes. We show that at 1530 nm signal wavelength, DMG of five mode groups is reduced from 1.32 dB (without trench) to 0.45 dB (with trench) with gain in excess of 20 dB. Also, the mode spacing ∆neff increases from 4.9× 10^-4 to 5.1 × 10^-4. Over the C-band, we have achieved more than 20 dB amplification and nearly 1 dB gain excursion while maintaining sufficient mode spacing ∆neff > 5.1× 10^-4 to avoid mode coupling due to macro-bending.

Simultaneously spatially and temporally focused femtosecond vortex beams for laser micromachining

Pavel Polynkin, Weibo Cheng, and Xiao-Long Liu

Doc ID: 332607 Received 29 May 2018; Accepted 09 Jul 2018; Posted 30 Jul 2018  View: PDF

Abstract: We combine conventional beam shaping with the simultaneous spatial and temporal focusing (SSTF), to generate femtosecond SSTF vortex beams. We demonstrate the utility of these beam structures by producing single-shot encryption of doughnut-shaped ablation marks on back surfaces of glass plates.The SSTF enables this type of machining by significantly reducing the nonlinear beam distortions on propagation through the glass.

Analytic treatment of beam quality and power efficiency in high power transverse flow Diode Pumped Alkali Laser

Tom Gavrielides, Laverne Schlie, Robert Loper, Michael Hawks, and Glen Perram

Doc ID: 332669 Received 29 May 2018; Accepted 25 Jun 2018; Posted 24 Jul 2018  View: PDF

Abstract: The performance of 100 kW Rb-He Diode Pumped Alkali Laser (DPAL) system is predicted, including power scaling, optical efficiency, and beam quality. A transverse flow geometry with longitudinal diode pumping produces a nonlinear temperature profile in the flow direction, with temperature increasing by 124 K for a 0.5 m/s flow rate and a 30 kW/cm2 pump intensity. The optical-to-optical efficiency is 70% and the tilt corrected Strehl is 0.545 for this slow flow, 45 ms residence time design. By increasing the flow speed to 15 m/s (1.5 ms residence time) the efficiency is improved to 82% and the laminar flow beam quality is near the diffraction limit, Strehl > 0.99. Beam quality is adversely affected at higher helium pressure for the slow flow conditions.

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