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Polarization output power stabilization of a vertical-cavity surface-emitting laser

Salam Ahmed and Zabih Ghassemlooy

Doc ID: 326091 Received 19 Mar 2018; Accepted 22 May 2018; Posted 24 May 2018  View: PDF

Abstract: This paper provides an experimental investigation of the polarization stabilization at the output power of an 850 nm vertical-cavity surface-emitting laser (VCSEL) with optical feedback (OF) and a range of polarization angles, OF strength and the bias current. The VCSEL’s polarization stabilization is evaluated using the extinction ratio measurements of the optical output power of polarization modes of the VCSEL. The results clearly show that, rotation of the polarization angle and the OF level can radically change the polarization stabilization of VCSEL. Both the polarization angle and OF introduce polarization switching (PS) and instability in the optical output power of the VCSEL. Consequently, these lead to performance degradation of VCSEL in terms of the operating point and the modulation bandwidth. At a fixed OF of -7dB, polarization destabilization is first observed at 450 with the increasing level of polarization angle. Whiles for fixed polarization angles of 900 and 400, polarization destabilization is observed at -14 dB and -14.5 dB, respectively with increasing level of orthogonal OF. We show that, with parallel OF, no PS is observed over the entire OF level. The results are also indicating that the VCSEL with no polarization angle requires higher level of OF to ensured PS compared with the case with the polarization angle.

Switchable 10, 20, and 30 GHz Region Photonics-based Microwave Generation using Thulium-Doped Fluoride Fiber Laser

Nurul 'Atiqah Ahmad, Samsul Dahlan, Noran Cholan, Harith Ahmad, and Zian Cheak Tiu

Doc ID: 325919 Received 13 Mar 2018; Accepted 18 May 2018; Posted 24 May 2018  View: PDF

Abstract: In this work, switchable 10, 20, and 30 GHz region photonics-based microwave generation in a fiber laser cavity is proposed and demonstrated. The microwave generation is based on the beating of a dual-wavelength thulium-doped fluoride fiber (TDFF). With the aid of a micro air gap in a fiber adapter, single, double and triple Brillouin spacing are able to be generated in a single fiber laser cavity without re-routing the cavity. The wavelength spacing of the dual wavelength that are induced by the single, double and triple Brillouin spacing are 0.084 nm, 0.166 nm and 0.254 nm respectively, at the center wavelength of 1490 nm. In addition, numerical calculation is performed using MATLAB to prove the generation of microwave signals at 11.34 GHz, 22.44 GHz, and 34.3 GHz. With the advantage of switch-ability among 10, 20 and 30 GHz region, the proposed photonics-based microwave generation is promising for the advancement of 5G technologies.

Self-focusing of Elliptic-Gaussian laser beam in relativistic ponderomotive plasma using ramp density profifile

Harish Kumar, Dr. Munish Aggarwal, Richa ., and Tarsem Gill

Doc ID: 312287 Received 24 Nov 2017; Accepted 17 May 2018; Posted 18 May 2018  View: PDF

Abstract: The propagation characteristics of elliptic Gaussian beam in the non-uniform plasma have been investigated by taking into account the combined effects of relativistic and ponderomotive type of nonlinearity. Self-trapping, self-phase modulation and beam width variation with propagation distance are given particular attention in the study. It is observed that plasma density function significantly affect the propagation behavior of the beam. Beam radius along x-axis and y-axis separately influenced due to density function which as a result of cross focusing phenomenon result in the reduction of effective beam radius during propagation of the beam. Longitudinal phaseshift increases in present case in comparison to uniform plasma. Self-trapping is also observed, which is however not comparable with that of cylindrically symmetrical Gaussian beam. We have used variational approach to setup the coupled nonlinear differential equations for the beam widthparameters along x and y-axis and longitudinal phase of the beam.

Vapor-cell frequency reference for short-wavelength transitions in neutral calcium

Steve Peil, Bryan Hemingway, Thomas Swanson, James Hanssen, and Jennifer Taylor

Doc ID: 325084 Received 28 Feb 2018; Accepted 17 May 2018; Posted 18 May 2018  View: PDF

Abstract: We have characterized the molecular tellurium (Te2) spectrum in the vicinity of the 4 nm 1S0-1P1 and the 431nm 3P1-3P0 transitions in neutral calcium. These transitions are relevant to optical clocks for atomic-beam characterization and cooling (4 nm) and enhanced detection (431nm). The use of a Te2 vapor cell as a frequency reference has many advantages over other laser stabilization techniques, and we discuss an application to measuring the instability due to the second-order Doppler shift in a calcium beam clock.

Employing coupled cavities to increase the cooling rate of a levitated nanosphere in the resolved sideband regime

Mohammad Ali Abbassi and Khashayar Mehrany

Doc ID: 326072 Received 16 Mar 2018; Accepted 17 May 2018; Posted 18 May 2018  View: PDF

Abstract: In this paper we investigate cooling of a levitated nanosphere in a system of coupled cavities in the resolved sideband regime. Thanks to the presence of an extra resonance in the coupled cavity cooling system, the coupling strength can be maximized at the optimum detuning. In this fashion, the intra-cavity photon number is increased and thereby the cooling rate is enhanced and the strong coupling regime is achieved without resorting to increased driving laser power. The underlying physics of the increased cooling efficiency in the here-proposed system of coupled cavities in the resolved sideband regime and that of the already reported system of coupled cavities in the unresolved sideband regime are significantly different from each other. Since the spectral density of the displacement of the particle can no longer be accurately approximated by the conventional Lorentzian lineshape in the strong coupling regime, a double Lorentzian lineshape is employed to accurately approximate the spectral density of the displacement of the particle and to provide analytical formulations for the cooling rate. The analytical expression given for the cooling rate is validated by numerical simulations.

Optical properties and electronic structure of Co and Fe based compounds

Viktor Lysiuk, Stanislav Rozouvan, and Vasil Stashchuk

Doc ID: 328428 Received 16 Apr 2018; Accepted 15 May 2018; Posted 18 May 2018  View: PDF

Abstract: Nanostructured grains of amorphous ferromagnetic alloy Co41Fe39B20 included in amorphous dielectric matrix SiO2 have been produced for investigation of its optical properties by ellipsometry methods in wavelength range from 0,24 to 1,0 µm and surface structure by AFM method. It has been shown formation of Fe clusters with Co and B inclusions producing intense and additional bands that are related with electron transitions from the base states located near Fe to impurity states formed by Co. The comparison of measured data for Co41Fe39B20 with theoretically calculated for Co2Fe2B demonstrated that intensive absorption bands in Fe-Co-B compounds are formed in result of transition also from s-, p- states of B to electronic states near Fe and Co. Sufficient widening of energy zones, located above Fermi level is happening due to strong scattering of electrons, participated in light absorption, as well as finite lifetime of excited electrons, what has led to sufficient widening of appropriate bands in absorption spectrum σ(hν).

Design of polarization splitting devices with ideal transmission and anisotropy considerations

Hossein Eskandari, Amir Reza Attari, and Mohammad Saeed Majedi

Doc ID: 322873 Received 12 Feb 2018; Accepted 15 May 2018; Posted 18 May 2018  View: PDF

Abstract: In this paper, we introduce the generalized design of nonmagnetic homogeneous polarization splitting devices (polarization deflector/lateral shifter) based on linear area-preserving transformations for an arbitrary incident angle. Also, by employing the Brewster angle condition, we derive a quadratic equation for principal values of the permittivity tensor that leads to the reflectionless splitting of two orthogonal polarizations for a normally impinging wave. The minimum in-plane anisotropy condition is then derived. The Brewster angle method offers significantly less anisotropy compared to the transformation optical design for larger deflection angles/lateral shifts in the normal incidence case. Finally, for an obliquely incident wave, we show that by using a uniaxial material (zero in-plane anisotropy), we can achieve similar functionality. The proposed devices can separate the polarizations of the incident wave by creating a desired angle or lateral shift between TE and TM polarizations. The functionality of the proposed designs is confirmed by the commercial finite-element-based software COMSOL Multiphysics.

A differential two-photon spectroscopy for nondestructive temperature measurements of cold light atoms in magneto-optical trap

Vladimir Sautenkov, Sergei Saakyan, A. Bobrov, Evgeniya Vilshanskaya, Boris Zelener, and Boris Zelener

Doc ID: 322883 Received 16 Feb 2018; Accepted 15 May 2018; Posted 18 May 2018  View: PDF

Abstract: A differential two-photon spectroscopic technique for measurement of atomic temperature in the working magneto-optic trap (MOT) was demonstrated. We performed experimental and theoretical studies of two-photon resonances on Rydberg transitions in cold 7Li atoms by using counter and co-propagating laser beams. By analyzing the spectral shapes a dependence of Rabi broadening and Doppler broadening on total intensity of cooling laser beams was obtained. The temperature of 7Li atoms in MOT was estimated. Our theoretical and experimental results are in a reasonably good agreement. Developed approach for temperature measurements can be applied to cold atoms in different traps, including confined hydrogen and antihydrogen atoms.

Efficient optical refrigeration in Yb3+:YLiF4 at cryogenic temperatures via pulsed excitation

Guang-Zong Dong, Kaishun Zou, and Juncheng Liu

Doc ID: 324767 Received 22 Feb 2018; Accepted 14 May 2018; Posted 18 May 2018  View: PDF

Abstract: A theoretical cooling scheme based on pulsed excitation is presented to facilitate efficient optical refrigeration at cryogenic temperatures. The mechanism of optical refrigeration with pulsed excitation is described by a simplified cooling model founded on density matrix. Simulated results show that, for the Yb3+:YLiF4 crystal with doping concentration of 10% and background absorption of 10–4 cm–1, optical refrigeration via picosecond pulsed excitation is competitive at temperature of lower than 100 K due to its high cooling efficiency, and may advance the cooling temperature to the boiling point of nitrogen.

Numerov Schrödinger Solver with Complex Potential Boundaries for Open Multilayer Heterojunction System

Zhiyuan Lin, Zhuoran Wang, Guohui Yuan, and Jean-Pierre Leburton

Doc ID: 326682 Received 23 Mar 2018; Accepted 14 May 2018; Posted 18 May 2018  View: PDF

Abstract: An efficient and stable algorithm based on the Numerov method to solve the Schrödinger equation with complex potential boundaries (NCPB) in open multilayer heterojunction systems is presented. The NCPB solver provides the complex expressions of the system eigenvalues to obtain the quasi-bound states (QBSs) energies and lifetimes. Examples of applications ranging from electron tunneling from an accumulation layer across a single AlGaAs barrier, to resonant tunneling through double barriers and QBSs in a multilayer quantum cascade laser (QCL) are discussed. These examples of applications show that the NCPB is a powerful tool for investigating, designing and optimizing multilayer heterojunction devices.

Wideband second harmonic generation using multiple tilted gratings in planar waveguide

Pragati Aashna and Krishna Thyagarajan

Doc ID: 326339 Received 19 Mar 2018; Accepted 12 May 2018; Posted 15 May 2018  View: PDF

Abstract: In this paper, we propose a device based on planar waveguides with multiple slanted quasi phase matching gratings to achieve significant increase in the bandwidth of second harmonic generation. We show that by an appropriate design of the device, the efficiency of second harmonic generation as a function of input pump frequency can be flattened significantly. The design using slant gratings allow for the fundamental and second harmonic to be non-collinear and thus resulting in ease of collection of the generated wave. Numerical simulations are performed in a potassium titanyl phosphate (KTP) planar waveguide and we show the analysis and results for increased bandwidth using two, three and four gratings which can be easily extended to more number of gratings without any loss of generality.

Simulation of THz generation and propagation from photo-Dember emitters

Lewis Maple, Paul Gow, and Vasilis Apostolopoulos

Doc ID: 323272 Received 13 Mar 2018; Accepted 11 May 2018; Posted 15 May 2018  View: PDF

Abstract: We demonstrate a simulation of lateral photo-Dember THz emitters in two dimensions using the drift diffusion equation coupled to a finite differences time domain (FDTD) model with a far-field algorithm that can take into account the angular spectrum of emission and propagation. We show that the dynamics of the system are more dependent on the currents traveling perpendicular to the semiconductor surface, as opposed to just the lateral currents as previously thought. The 2D simulation is needed in order to correctly represent experiments that measure emission out of lateral photo-Dember emitters.

The Relationship between Morphology and Transparency in Glass-Ceramic Materials

Nicholas Borrelli, Charlene Smith, and Alexandra Mitchell

Doc ID: 320833 Received 31 Jan 2018; Accepted 10 May 2018; Posted 15 May 2018  View: PDF

Abstract: This paper is an attempt to understand and interpret the optical scattering in composite materials. It focuses on phase-separated glasses and glass-ceramics that maintain transparency at high crystal content. Two approaches aimed at understanding optical scattering are investigated for each example material: 1) a single particle approach and 2) a correlation function approach based on the spatial distribution of the refractive index profile of the material pioneered by P. Debye. Both methods have shortcomings: the single particle approach cannot take the material’s morphology into account whereas it is non-trivial to determine the correlation function. Regardless, the preferred approach is determined for each of the materials investigated. It is shown that optical scattering in glass ceramics can be controlled to produce a transparent material if the glass ceramic has a bulk fine-grained structure without an easily recognized ‘grain size’.

Dynamic PIT modulator and excellent absorber based terahertz planar graphene metamaterial

Hui Xu, Cuixiu Xiong, Zhiquan Chen, Mingfei Zheng, Mingzhuo Zhao, Baihui Zhang, and Hongjian Li

Doc ID: 326012 Received 13 Mar 2018; Accepted 08 May 2018; Posted 09 May 2018  View: PDF

Abstract: Narrow linewidths spectra in terahertz band are obtained by a novel planar metamaterial structure. Two different kinds of graphene which lie on a silica substrate respectively play the part of optical bright and dark mode. An obvious plasmon induced transparency can arise within a broad resonance spectrum, which results from the destructive interference between the two modes. We have investigated the spectral location and line shape, and then we find that they can be successfully tuned by shifting the Fermi energy. Furthermore, the absorption rate is up to fifty percent. Thus, the narrow plasmon induced transparency phenomena render our nano plasmonic system ideal for excellent modulator and novel absorber.

Metal Island Film Based Plasmonic Triple-layer Absorber

Ting Ji, Hui Li, Wenyan Wang, Xueyan Wu, Yanxia Cui, Zhigang Jia, hua wang, and Yuying Hao

Doc ID: 326021 Received 16 Mar 2018; Accepted 08 May 2018; Posted 09 May 2018  View: PDF

Abstract: High efficiency, broadband plasmonic triple-layer absorbers comprised of an ultrathin Ag island layer, a SiO2 spacer and a reflective Ag substrate are fabricated by magnetron sputtering. Experimental results reveal that surface morphologies of the fabricated Ag island film do not have regular profiles, but appear more like two or more hemi-ellipsoids randomly overlap each other. Different from previous reports which modelled the metal island film using squared patches or regular hemi-ellipsoids, we construct the numerical model by simplifying the top metal island film as an array of overlapping hemi-ellipsoids aiming for explaining the measured efficient absorption over a broad wavelength range more accurately. Through comparison, it is found that the overlapping hemi-ellipsoids can produce an additional absorption peak at the long wavelength range by the excitation of hot spot effect with respect to the structure with two isolated hemi-ellipsoids. Other strong absorption peaks at short wavelength ranges are also analysed systematically. By tuning the geometry of the ellipsoids and the size of overlapping region, the absorption performance of the constructed overlapping model can be tuned. In reality, the geometries of the isolated islands are non-uniform, yielding the broad high efficiency absorption band witnessed in experiment. Our work contributes to the design of efficient light devices for application in the area of solar energy harvesting and thermal emission tailoring.

Taming Parasitic Resonant Thermal Emission by Tamm Plasmon Polaritons for the Mid-Infrared

Gerald Pühringer and Bernhard Jakoby

Doc ID: 323329 Received 21 Feb 2018; Accepted 08 May 2018; Posted 09 May 2018  View: PDF

Abstract: We investigated the concept of a 1D layered structure for resonant selective thermal emission by excitation Tamm plasmon polaritons (TPPs). The modeled and simulated TPP structures for the mid-IR spectral region yield a promising approach for integrated sensing applications. In particular, the TPP structure is composed of an aperiodic multilayer stack of dielectric layers (silicon and silica) on a planar metallic surface acting as a heater and thus emitter for thermal radiation. By varying the layer-depths, this design is highly optimizable for individual specifications, such as for enhancing the thermal emittance near to unity around a target wavelength and achieving a resonance with high Q-factor. Here, for demonstration purposes we chose λ=4.26 µm as target emission wavelength (corresponding to a major CO2 absorption line). However, considering a larger spectral range within the mid-IR region, parasitic resonances emerge in a more or less unpredictable manner and lead to multiband emission. A transfer matrix approach and genetic-algorithm (GA) optimization were used to identify feasible stack configurations and characterize the behavior of parasitic resonances. In order to analyze and control the emergence of parasitic emission, different parameters characterizing the stack-metal composition were set. In particular, we found that keeping constraints on the number of dielectric layers and their individual thicknesses allow effective control of parasitic emission while also facilitating modern microlayer fabrication processes. Even though those constraints can hamper the enhancement of the Q-factor at the target resonance, highly performant configurations and parameters for the TPP structures could be identified. Each configuration corresponds to a particular choice of substrate metals (Ag or W), number of layers and individual layer thicknesses. The behavior of the target and the parasitic resonances was discussed by using concepts of topological photonics and lumped parameter models.

Evanescent depth enhanced photon-exciton coupling in evanescent vacuum

Juanjuan Ren, He Hao, Zhiyuan Qian, Xueke Duan, Fan Zhang, Tiancai Zhang, Qihuang Gong, and Ying Gu

Doc ID: 324710 Received 22 Feb 2018; Accepted 07 May 2018; Posted 09 May 2018  View: PDF

Abstract: Electromagnetic vacuum engineering in nanostructures can be used to tailor the light-emitter interaction at subwavelength scale. Here, by embedding a nano-cavity quantum electrodynamic system in evanescent vacuum, we theoretically investigate evanescent depth enhanced photon-exciton coupling. Owing to faster exponential decay of an evanescent wave, smaller evanescent depth leads to larger coupling coefficient enhancement. The enhanced coupling coefficients are also demonstrated by changing Ag nanorod size and the gap distance between the nanoparticle and plate. To significantly enhance the absolute value of the coupling coefficients, the Ag cylindrical nanorod can be replaced by the Ag pyramid or bipyramid. Evanescent vacuum induced strong photon-exciton coupling would have a significant influence on fundamental physics of subwavelength-confined cavity quantum electrodynamics and on-chip quantum information processing and scalable quantum networks.

Designing fiber tapers for tunable dispersive-wave generation from agile Yb-based pump lasers

Jesper Laegsgaard

Doc ID: 326991 Received 26 Mar 2018; Accepted 07 May 2018; Posted 09 May 2018  View: PDF

Abstract: The generation of wavelength-tunable dispersive waves in tapered optical fibers is modeled. The pump source is taken to be a femtosecond laser with emission wavelength at 1030 nm, appropriate for an Yb-based fiber laser, and variable pulse energy and duration. The variable pulse properties translate into wavelength tunability of the dispersive waves across the visible spectrum due to the fiber tapering. This contribution investigates taper design strategies to obtain features such as spectral isolation of the visible output, low-noise operation with optimal spectral density, and short output pulses.

A broadband laser driven electromagnetically induced transparency in three-level systems with a double Fano continuum

Duc Nguyen, Khoa Doan, Thai Thanh, quy ho, Van Cao, and Wiesław Leoński

Doc ID: 324553 Received 20 Feb 2018; Accepted 05 May 2018; Posted 09 May 2018  View: PDF

Abstract: We discuss electromagnetically induced transparency (EIT) phenomenon for a model in which a structured continuum is described by so-called double Fano structure - instead of one autoionizing (AI) state, two such states are embedded in a flat continuum. Such Fano structure is the upper level of a Λ-like three-level systems, and is coupled to two lower ones by an external laser field involving δ-correlated, Gaussian, Markov process (white noise), simulating realistic conditions of the experiment. For such a system we derived and solved a set of coupled stochastic integro-differential equations in the stationary regime, obtaining exact formulas determining the electric susceptibility of the system. Dispersion and absorption spectra of the medium susceptibility were calculated and compared with those already discussed in the literature. We have shown that the presence of additional AI level considerably changes the structure of transparency windows, and how noisy excitation influences the EIT processes.

Numerical Surface-Corrected Nonlocal Electrodynamic Model for Nanophotonic Structures

Hao Yang, Xiang Meng, Shuhao Wu, Jerry Dadap, and Richard Osgood

Doc ID: 318218 Received 12 Jan 2018; Accepted 05 May 2018; Posted 09 May 2018  View: PDF

Abstract: Recent work has shown the significance of a nonlocal dielectric response and surface correction for nanometer-length-scale plasmonic structures. In this paper, we propose a new surface hydrodynamic model, which incorporates such nonlocality and surface correction. Our approach, which is based on the hydrodynamic model (HDM), uses a numerical approach based on full-wave numerical computation and thus enables calculation of surface plasmon polaritons (SPP) fields. The model also introduces a discontinuity in the normal component of the electric displacement at the inter- face by taking into account the screening of the electrons at the interface. The method makes use of the Feibelman d-parameter approach for the surface correction by equating the corrected Fresnel reflection of a p-polarized incident field across a planar interface. To demonstrate our method, we first examine numerical calculation of SPP propagation at a single interface structure; this work is then followed by a demonstration for a set of more complex thin-film structures. The latter demonstrates that our method suitable for use in numerical modeling of complex nanophotonic structures.

Optical Switching Through Graphene-Induced Exceptional Points

Dimitrios Chatzidimitriou and Emmanouil Kriezis

Doc ID: 319947 Received 19 Jan 2018; Accepted 04 May 2018; Posted 09 May 2018  View: PDF

Abstract: The switching properties of coupled nanophotonic waveguides under the influence of a loss induced exceptional point are analytically and numerically investigated. The specific requirements for switching/routing functionality are determined and an analytically predicted lower boundary for the insertion losses is established. These passive PT-Symmetric dynamics are demonstrated in a silicon photonic coupler through the use of graphene layers. Graphene's chemical potential is properly tuned, in accordance with the exceptional point requirements, for the electro-optic control of its surface conductivity. All analytically derived findings are numerically verified enabling linear, low-loss, and high extinction ratio switching elements. Finally, a polarization dependent photonic switch is showcased based on both exceptional points and graphene's anisotropic surface conductivity.

Ponderomotive interaction of high-power cylindrical vector beams with plasma

Zhili LIN, Xudong Chen, Weibin Qiu, Ziyang Chen, and Jixiong Pu

Doc ID: 323097 Received 12 Feb 2018; Accepted 02 May 2018; Posted 03 May 2018  View: PDF

Abstract: The spatio-temporal evolution of high-power cylindrical vector (CV) beam interaction with plasma is numerically investigated by using the finite-difference time-domain (FDTD) method. According to the theory of ponderomotive nonlinearity of plasma, the Drude model with both modified resonance frequency and modified collision frequency is given for depicting the dispersive and dissipative permittivity of plasma with the presence of high-power laser. The corresponding algorithms of FDTD method are proposed for numerically simulating the nonlinear dielectric model and artificially generating the radially and azimuthally polarized CV beams. The simulation results about the 3D dynamic interaction processes between the high-power CV beams and plasma are presented and discussed, by which we find that the plasma has different modulation effects on the two types of CV beams with different polarization states. The anticipated phenomena such as the self-focusing of high-power laser beam in plasma and the self-tunneling of plasma are also verified. This study provides a transient and dynamic simulation method for laser-plasma interaction and also exploits a new approach for the field modulation of laser beams by plasma.

Photon Catalysis and Quantum State Engineering

Richard Birrittella Jr., Christopher Gerry, and Morad El Baz

Doc ID: 324658 Received 23 Feb 2018; Accepted 02 May 2018; Posted 03 May 2018  View: PDF

Abstract: Photon catalysis is a technique by which a readily available Gaussian state of light prepared in one mode is incident upon a beam splitter with a discrete number of photons, $q$, prepared in another mode; the resulting two-mode state is then subjected to single-photon resolving detection for $q$ photons on one of the output modes. By employing beam splitters of different transmissivities and reflectivities, the subsequent single-mode state is shown to possess non-classical properties such as quadrature squeezing and sub-Poissonian statistics. We consider the case in which the input state is the most general of pure single-mode Gaussian states: a squeezed coherent state. Noting the Gaussianty of the initial state, we demonstrate non-Gaussianty of the photon-catalyzed state by analyzing the quadrature uncertainty product and explicitly illustrate it through the Wigner quasi-probability distribution. We extend this technique to the two-mode squeezed states, whereby we perform photon catalysis on one mode of a two-mode squeezed vacuum state. The resulting correlated two-mode state may have applications in fundamental tests of quantum mechanics such as violations of Bell's inequalities as the detection loophole can be closed due to the non-Gaussianity of the photon-catalyzed state. We also generalize our method to include state projective measurements for $l\neq q$ photons.

Ultra-low phase noise microwave oscillator based on an IF crystal resonator-amplifier and a microwave photonic frequency transposer

S.Esmail Hosseini, Seyyed Saied Shojaeddin, and Habibollah Abiri

Doc ID: 327356 Received 02 Apr 2018; Accepted 02 May 2018; Posted 03 May 2018  View: PDF

Abstract: Resonator Q-factor and amplifier flicker noise are the most important parameters that determine phase noise of microwave oscillators. Q-factor of intermediate frequency (IF) crystal resonators at IF frequencies can be larger than that of microwave resonators at microwave frequencies. Besides, flicker noise of IF amplifiers can be less than that of microwave amplifiers. One of the well known usual ways to implement low phase noise microwave oscillators is to use ultra-low phase noise IF crystal oscillators and frequency multipliers. In this paper a new method to implement such oscillators based on IF crystal resonators and amplifiers, called transposed frequency microwave oscillator, is proposed. In the proposed structure, a microwave photonic frequency transposer is used to down-convert RF to IF followed by a high-Q IF crystal filter and low flicker noise IF amplifier and then up-converting IF to RF frequency. This novel method in comparison to the well known multiplier based microwave oscillators presents significant advantages. In this paper, the proposed new structure is introduced and a theoretical model is developed to study its performance. Oscillation frequency and amplitude, equivalent Q-factor, phase noise, etc., are theoretically studied and compared with the performances of the well known microwave oscillators based on frequency multipliers and optoelectronic oscillators (OEOs). It is shown that the phase noise of the proposed microwave oscillator can be less than -130 dBc/Hz at 100 Hz from 10 GHz carrier with noise floor less than -165 dBc/Hz.

Numerical modeling of mid-infrared ultrashort pulse propagation in Er3+: fluoride fiber amplifiers

Simon Duval, Michel Olivier, Louis-Rafaël Robichaud, Vincent Fortin, Martin Bernier, Michel Piche, and Real Vallee

Doc ID: 312937 Received 30 Nov 2017; Accepted 27 Apr 2018; Posted 03 May 2018  View: PDF

Abstract: We present a numerical model to study the amplification and spectral conversion of ultrashort pulses at 2.8 µm in Er3+: fluoride fibers. This model includes accurate measurements of the gain and Raman properties of fluorozirconate fibers and agrees well with the experimental results. Interesting new features of such mid-infrared fiber amplifier are discussed for varying seeding conditions and fiber parameters. Among these features is the attractor property of the amplifier that significantly increases the output stability of the tunable ultrafast system. When using the appropriate seed and fiber parameters, the model predicts the generation of a mid-infrared supercontinuum output with more than 4 W of average power or the generation of tunable ultrashort pulses above 3 µm with peak powers exceeding 400 kW.

Research on the third harmonic generation with position dependent mass in a quantum well

Qiucheng Yu, Kangxian Guo, Meilin Hu, Zhongmin Zhang, Zhihai Zhang, and Dongfeng Liu

Doc ID: 326313 Received 23 Mar 2018; Accepted 26 Apr 2018; Posted 27 Apr 2018  View: PDF

Abstract: In this paper, the energy levels and the wave functions of the schrödinger equation with position dependent mass (PDM) are theoretically deduced, and they are brought into the nonlinear optical third harmonic generation (THG). We find that the peak of the third harmonic coefficient becomes larger and occurs a blue shift under the condition of variable mass. Moreover, with the increment of mass variable k, the energy interval Eij decreases, which makes the coefficients suffer a red shift, and the absolute value of the matrix elements product |M12M M34M41| presents different monotonicity, that makes the peaks value of coefficient change regularly.

An Improved scheme for modelling a spaser made of identical gain elements

Tharindu Warnakula, Mark Stockman, and Malin Premaratne

Doc ID: 320965 Received 31 Jan 2018; Accepted 22 Apr 2018; Posted 25 Apr 2018  View: PDF

Abstract: Simulation of the most general configuration of a spaser where each gain element is assumed to have distinct behaviour is almost intractable with current computing technologies. Hence, here we consider a representative, yet simple enough system with all possible interactions allowed, in which all gain elements have identical features including two energy levels, to gain deeper understanding of the operational characteristics. We reason in an intuitively sound, yet mathematically rigorous way, how to exploit the symmetry of the most efficient method currently available to reduce the size of the problem by order O(M) , where M is the size of the truncated plasmon number state.

Light scattering in glass-ceramics: revision of the concept

Mikhail Shepilov, Olga Dymshits, and Alexander Zhilin

Doc ID: 322870 Received 13 Feb 2018; Accepted 19 Apr 2018; Posted 20 Apr 2018  View: PDF

Abstract: Transparency of glass-ceramics is limited by light scattering connected with their structure (nano(micro)-sized crystals distributed within the residual glass). We digitized and analyzed graphical data on transparency of glass-ceramics presented in literature and demonstrated that, for most glass-ceramics, wavelength dependence of scattering coefficient is described by the power law with the constant exponent (-p). The values of p are often markedly greater than the Rayleigh value 4 and may be as much as 9. This conclusion is extremely important for the development of new materials and contradicts the generally accepted opinion that p ≤ 4 for glass-ceramics. Similar behavior of light scattering was observed earlier in phase-separated glasses and is known as anomalous light scattering.

Line-current model for linear and nonlinear optical properties of thin elongated metallic rod antennas

Maxim Nesterov, Martin Schäferling, Ksenia Weber, Frank Neubrech, Harald Giessen, and Thomas Weiss

Doc ID: 319861 Received 16 Jan 2018; Accepted 16 Apr 2018; Posted 19 Apr 2018  View: PDF

Abstract: Thin elongated rod antennas with a diameter smaller than the skin depth exhibit surface plasmon polariton modes that can propagate along the antenna while being reflected at the antenna ends. In the line-current model, a current is associated with these modes in order to approximate the optical properties of the antennas. We find that it is crucial to correctly derive the reflection of the surface plasmon polariton modes at the antenna ends for predicting the resonance position and shape accurately. Thus, the line-current model allows for deriving the wavelength scaling behavior of plasmonic near fields as well as the emitted third-harmonic intensity efficiently. Neglecting the frequency dependence of the nonlinear susceptibility, we find that the third-harmonic intensity of such metallic rod antennas scales as the fourth power of the frequency, whereas it decreases with the twelfth power within the limit of the generalized Miller's rule.

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