Electro-optic mapping systems of electric-field using CW laser diodes

Two novel systems are proposed to perform the electro-optic (EO) mapping of the electric-field strength close to electrode structure using CW laser diodes. By these systems, mappings of both static (DC) and high-frequency electric-field can be obtained. For the static field, the field is chopped to increase the sensitivity performance. For the high-frequency field, an intensity modulation laser, instead of a pulse laser, is used to perform the mapping measurement in frequency domain, instead of in time domain. This approach greatly simplifies the system. An experiment set-up using a vertical cavity surface emitted laser diode (VCSEL) of a wavelength 850 nm and its mapping results for a coplanar waveguide (CPW) with the signal frequency around 1 GHz are reported.     

Separated AlxIn1−xN quantum dots grown by plasma-reactive co-sputtering

Separated Al_xIn_1−xN quantum dots (QDs) embedded in amorphous AlN films have been produced by radio-frequency co-sputtering technique on silicon (1 1 1) and quartz glass substrates. The mean size and density of Al_xIn_1−xN QDs can be conveniently monitored by deposition parameters. Transparent electron microscope, and X-ray diffraction were used to detect the structure of the Al_xIn_1−xN QDs system; field-emission scanning-electron microscope was adopted to measure the surface morphology and anticipate the size of the QDs; X-ray photoelectronic spectroscopy was used to measure the stoichiometric ratios of the QDs.     

The AME2016 atomic mass evaluation (I). Evaluation of input data; and adjustment procedures

This paper is the first of two articles (Part I and Part II) that presents the results of the new atomic mass evaluation, AME2016. It includes complete information on the experimental input data (also including unused and rejected ones), as well as details on the evaluation procedures used to derive the tables of recommended values given in the second part. This article describes the evaluation philosophy and procedures that were implemented in the selection of specific nuclear reaction, decay and mass-spectrometric results. These input values were entered in the least-squares adjustment for determining the best values for the atomic masses and their uncertainties. Details of the calculation and particularities of the AME are then described. All accepted and rejected data, including outweighted ones, are presented in a tabular format and compared with the adjusted values obtained using the least-squares fit analysis. Differences with the previous AME2012 evaluation are discussed and specific information is presented for several cases that may be of interest to AME users. The second AME2016 article gives a table with the recommended values of atomic masses, as well as tables and graphs of derived quantities, along with the list of references used in both the AME2016 and the NUBASE2016 evaluations (the first paper in this issue).     

基于CompactRIO的四旋翼飞控实时仿真平台设计

针对四旋翼无人机实时飞行控制系统的控制算法设计与参数整定,设计了一种基于CompactRIO的飞行控制系统实时仿真平台,该平台使用两台CompactRIO作为主控制器,分别在其嵌入式实时系统(VxWorks)中运行Simulink设计的无人机动力学模型与飞行控制系统模型,并使用LabVIEW开发PC上位机监控程序,用于调整飞行状态和整定控制参数。经试验证明,该平台实用性强,可视化程度高,实时性好,能较好地对四旋翼飞控系统进行实时仿真验证。     

Analytic soliton solutions of cubic‐quintic Ginzburg‐Landau equation with variable nonlinearity and spectral filtering in fiber lasers

In fiber lasers, the study of the cubic‐quintic complex Ginzburg‐Landau equations (CGLE) has attracted much attention. In this paper, four families (kink solitons, gray solitons, Y‐type solitons and combined solitons) of exact soliton solutions for the variable‐coefficient cubic‐quintic CGLE are obtained via the modified Hirota method. Appropriate parameters are chosen to investigate the properties of solitons. The influences of nonlinearity and spectral filtering effect are discussed in these obtained exact soliton solutions, respectively. Methods to amplify the amplitude and compress the width of solitons are put forward. Numerical simulation with split‐step Fourier method and fourth‐order Runge‐Kutta algorithm are carried out to validate some of the analytic results. Transformation from the variable‐coefficient cubic‐quintic CGLE to the constant coefficients one is proposed. The results obtained may have certain applications in soliton control in fiber lasers, and may have guiding value in experiments in the future.

     

Collimating Montel mirror as part of a multi‐crystal analyzer system for resonant inelastic X‐ray scattering

Advances in resonant inelastic X‐ray scattering (RIXS) have come in lockstep with improvements in energy resolution. Currently, the best energy resolution at the Ir L₃‐edge stands at ～25 meV, which is achieved using a diced Si(844) spherical crystal analyzer. However, spherical analyzers are limited by their intrinsic reflection width. A novel analyzer system using multiple flat crystals provides a promising way to overcome this limitation. For the present design, an energy resolution at or below 10 meV was selected. Recognizing that the angular acceptance of flat crystals is severely limited, a collimating element is essential to achieve the necessary solid‐angle acceptance. For this purpose, a laterally graded, parabolic, multilayer Montel mirror was designed for use at the Ir L₃‐absorption edge. It provides an acceptance larger than 10 mrad, collimating the reflected X‐ray beam to smaller than 100 µrad, in both vertical and horizontal directions. The performance of this mirror was studied at beamline 27‐ID at the Advanced Photon Source. X‐rays from a diamond (111) monochromator illuminated a scattering source of diameter 5 µm, generating an incident beam on the mirror with a well determined divergence of 40 mrad. A flat Si(111) crystal after the mirror served as the divergence analyzer. From X‐ray measurements, ray‐tracing simulations and optical metrology results, it was established that the Montel mirror satisfied the specifications of angular acceptance and collimation quality necessary for a high‐resolution RIXS multi‐crystal analyzer system.     

Calibration of a compact XUV soft X‐ray monochromator with a digital autocollimator in situ

A digital autocollimator of resolution 0.1 µrad (0.02 arcsec) serves as a handy correction tool for calibrating the angular uncertainty during angular and lateral movements of gratings inside a monochromator chamber under ultra‐high vacuum. The photon energy dispersed from the extreme ultraviolet (XUV) to the soft X‐ray region of the synchrotron beamline at the Taiwan Light Source was monitored using molecular ionization spectra at high resolution as energy references that correlate with the fine angular steps during grating rotation. The angular resolution of the scanning mechanism was <0.3 µrad, which results in an energy shift of 80 meV at 867 eV. The angular uncertainties caused by the lateral movement during a grating exchange were decreased from 2.2 µrad to 0.1 µrad after correction. The proposed method provides a simple solution for on‐site beamline diagnostics of highly precise multi‐axis optical manipulating instruments at synchrotron facilities and in‐house laboratories.     

Quantum Games under Decoherence

Quantum systems are easily influenced by ambient environments. Decoherence is generated by system interaction with external environment. In this paper, we analyse the effects of decoherence on quantum games with Eisert-Wilkens-Lewenstein (EWL) (Eisert et al., Phys. Rev. Lett. 83(15), 3077 1999) and Marinatto-Weber (MW) (Marinatto and Weber, Phys. Lett. A 272, 291 2000) schemes. Firstly, referring to the analytical approach that was introduced by Eisert et al. (Phys. Rev. Lett. 83(15), 3077 1999), we analyse the effects of decoherence on quantum Chicken game by considering different traditional noisy channels. We investigate the Nash equilibria and changes of payoff in specific two-parameter strategy set for maximally entangled initial states. We find that the Nash equilibria are different in different noisy channels. Since Unruh effect produces a decoherence-like effect and can be perceived as a quantum noise channel (Omkar et al., arXiv:1408.1477v1), with the same two parameter strategy set, we investigate the influences of decoherence generated by the Unruh effect on three-player quantum Prisoners’ Dilemma, the non-zero sum symmetric multiplayer quantum game both for unentangled and entangled initial states. We discuss the effect of the acceleration of noninertial frames on the the game’s properties such as payoffs, symmetry, Nash equilibrium, Pareto optimal, dominant strategy, etc. Finally, we study the decoherent influences of correlated noise and Unruh effect on quantum Stackelberg duopoly for entangled and unentangled initial states with the depolarizing channel. Our investigations show that under the influence of correlated depolarizing channel and acceleration in noninertial frame, some critical points exist for an unentangled initial state at which firms get equal payoffs and the game becomes a follower advantage game. It is shown that the game is always a leader advantage game for a maximally entangled initial state and there appear some points at which the payoffs become zero.     

Arbitrated Quantum Signature Scheme with Continuous-Variable Coherent States

Motivated by the revealing features of the continuous-variable (CV) quantum cryptography, we suggest an arbitrated quantum signature (AQS) protocol with CV coherent states. It involves three participants, i.e., the signer Alice, the verifier Bob and the arbitrator Charlie who is trustworthy by Alice and Bob. Three phases initializing phase, signing phase and verifying phase are included in our protocol. The security of the signature scheme is guaranteed by the generation of the shared keys via the CV-based quantum key distribution (CV-QKD) and the implementation process of the CV-based quantum teleportation as well. Security analysis demonstrates that the signature can be neither forged by anyone nor disavowed by the receiver and signer. Moreover, the authenticity and integrality of the transmitted messages can be ensured. The paper shows that a potential high-speed quantum signature scheme with high detection efficiency and repetition rate can be realized when compared to the discrete-variable (DV) quantum signature scheme attributing to the well characteristics of CV-QKD.     

Single-Photon Scattering Grating in a Waveguide-Cavity System

We investigate single-photon scattering grating in a one-dimensional waveguide coupled to a cavity embedded with a driven Λ-type three-level atom. The single-photon reflection amplitude and transmission amplitude in the waveguide are obtained via a real-space approach, respectively. By spatially modulating a classical control field to drive the three-level emitter, alternating regions of high reflection and absorption as well as high transmission and absorption of the single photon are generated in both directions of the waveguide, which acts as a kind of scattering grating. The proposed scheme may have the potential for the design of chip-integrated grating.