Optics Letters
5 stars based on
72 reviews
Plasma q-plate for generation and manipulation of intense optical vortices. An optical vortex is a light wave with a twisting wavefront around its propagation axis and null intensity in the beam center. Its unique spatial structure of field lends itself to a broad range of applications, including optical communication, quantum information, superresolution microscopy, and multi-dimensional manipulation of particles.
However, accessible intensity of optical vortices have been limited to material ionization threshold. This limitation might be removed by using the plasma medium. Here we propose the design of suitably magnetized plasmas which, functioning as a q-plate, chen ying electromagnetic pump liquid to a direct convertion from a high-intensity Gaussian beam into a twisted beam. A circularly polarized laser beam in the plasma accumulates an azimuthal-angle-dependent phase shift and hence forms a twisting wavefront.
Our three-dimensional particle-in-cell simulations demonstrate extremely high power conversion efficiency. The plasma q-plate can work in a large range of frequencies spanning from terahertz to the optical domain. Submitted 30 November, ; v1 submitted 22 September, ; originally announced September E 96, EdwardsQing JiaJulia M.
MikhailovaNathaniel J. We examine the feasibility of strongly-coupled stimulated Brillouin scattering as a mechanism for the plasma-based amplification of sub-picosecond pulses. In particular, we use fluid theory and particle-in-cell simulations to compare the relative advantages of Raman and Brillouin amplification over a chen ying electromagnetic pump liquid range of achievable parameters.
Submitted chen ying electromagnetic pump liquid September, ; v1 submitted 1 July, ; originally announced July Plasmas 23, Theory of electromagnetic wave frequency upconversion in dynamic chen ying electromagnetic pump liquid. Edwards chen ying electromagnetic pump liquid, Nathaniel J. Frequency upconversion of an electromagnetic wave can occur in ionized plasma with decreasing electric permittivity and in split-ring resonator-structure metamaterials with decreasing magnetic permeability.
We develop a general theory to describe the evolution of the wave frequency, amplitude, and energy density in an arbitrary homogeneous media with temporally decreasing refractive index.
We chen ying electromagnetic pump liquid that upconvertion of the wave frequency is necessarily accompanied by partitioning of the wave energy into low-frequency modes, which sets an upper limit on the energy conversion chen ying electromagnetic pump liquid. The efficiency chen ying electromagnetic pump liquid are obtained for both varying permittivity and varying permeability.
Submitted 19 April, ; originally announced April An online learning approach to dynamic pricing for demand response. In this paper, the problem of optimal dynamic pricing for retail electricity with an unknown demand model is considered. Under the day-ahead dynamic pricing a. Without knowledge on the aggregated demand function of its chen ying electromagnetic pump liquid, the retailer aims to maximize its retail chen ying electromagnetic pump liquid by sequentially adjusting its price based on the behavior of its customers in the past.
An online learning algorithm, referred to as piecewise linear stochastic approximation PWLSAis proposed. It is shown that PWLSA achieves the optimal rate of learning defined by the growth rate of cumulative regret. In particular, the regret of PWLSA is shown to grow logarithmically with respect to the learning horizon, and no other on-line learning algorithm can have the growth rate slower than that of PWLSA.
Simulation studies are presented using traces of actual day-ahead prices, and PWLSA compares favorably under both static and dynamically changing parameters. Submitted 4 April, ; originally announced April The pure gauge velocity solutions of hydrodynamic equations provide an analogous Wu-Yang monopole potential. The two cases of velocity in superfluid are equivalent to the two regions of Wu-Yang monopole potential. Due to the compressibility of superfluid, the physical models are limited, such as hard core and harmonic oscillator.
The results provide a new possibility for the simulation of Wu-Yang monopole. Submitted 7 April, ; v1 submitted 15 March, ; originally announced May This paper has been withdrawn by the author due to a crucial sign error in some equations.
Single image haze removal is a challenging ill-posed problem. The key to achieve haze removal is to estimate a medium transmission map for an input hazy image. In this paper, we propose a trainable end-to-end system called DehazeNet, for medium transmission estimation. DehazeNet takes a chen ying electromagnetic pump liquid image as input, and outputs its medium transmission map that is subsequently used to recover a haze-free image via atmospheric scattering model.
Specifically, layers of Maxout units are used for feature extraction, which can generate almost all haze-relevant chen ying electromagnetic pump liquid. We establish connections between components of the proposed DehazeNet and those used in existing methods. Experiments on benchmark images chen ying electromagnetic pump liquid that DehazeNet achieves superior performance over existing methods, yet keeps efficient and easy to use.
Submitted 17 May, ; v1 submitted 28 January, ; originally announced January Transistors are the fundamental building block of modern electronic devices. So far, all transistors are based on various types of semiconductor junctions. The most common bipolar-junction transistors and metal-oxide-semiconductor field-effect transistors contain p-n junctions to control the current, depending on applied biases across the junctions.
Thin-film transistors need metal-semiconductor junctions for injecting and extracting electrons from their channels. This could be the simplest transistor in the world, to our knowledge, not only in its structure, but also its fabrication process. Our results clearly show that this architecture can lead to a new class of low-cost transistors. Submitted 1 April, ; originally announced April Distance estimation is vital for localization and many other applications in wireless sensor networks WSNs.
Particularly, it is desirable to implement distance estimation as well as localization without using specific hardware in low-cost WSNs. As such, both the received signal strength RSS based chen ying electromagnetic pump liquid and the connectivity based approach have gained much attention.
The RSS based approach is suitable for estimating short distances, whereas the connectivity based approach obtains relatively good performance for estimating long distances.
Chen ying electromagnetic pump liquid the complementary features of these two approaches, we propose a fusion method based on the maximum-likelihood estimator MLE to estimate the distance between any pair of neighboring nodes in a WSN through efficiently fusing the information from the RSS and local connectivity.
Additionally, the method is reported under the practical log-normal shadowing model, and the associated Cramer-Rao lower bound CRLB is also derived for performance analysis.
Both simulations and experiments based on practical measurements are carried out, and demonstrate that the proposed method outperforms any single approach and approaches to the CRLB as well. Submitted 28 January, ; originally announced January A new and simple quantum key distribution scheme based on the quantum intensity correlation of optical twin beams and the directly local measurements of intensity noise of single optical beam is presented and experimentally demonstrated.
The noncloning of quantum systems and the sensitivity of the existing correlations to losses provide the physical mechamism for the security against eavesdropping. In the presented scheme the signal modulation and homodyne chen ying electromagnetic pump liquid are not needed. Submitted 8 April, ; originally announced April The unconditional entanglement swapping for continuous variables is experimentally demonstrated.
Two initial entangled states are produced from two nondegenerate optical parametric amplifiers operating at deamplification. Through implementing the direct measurement of Bell-state between two optical beams from each amplifier the remaining two optical beams, which have never directly interacted with each other, are entangled.
The quantum correlation degrees of 1. Submitted 25 December, ; v1 submitted 3 July, ; originally announced July An impurity solver for the dynamical mean field DMFT study of the Mott insulators is proposed, which is based on the second order perturbation of the hybridization function.
Submitted 7 November, ; originally announced November Software testing is an expensive and important task. Plenty of researches and industrial efforts have been invested on improving software testing techniques, including criteria, tools, etc. These studies can provide guidelines to select suitable test techniques for software engineers. However, in some engineering projects, business issues may be more important than technical ones, hence we need to lobby non-technical members to support our decisions.
In this paper, a well-known investment model, Nelson-Siegel model, is introduced to evaluate and forecast the processes of testing with different testing criteria. Through this model, we provide a new perspective to understand short-term, medium-term, and long-term returns of investments throughout the process of testing. A preliminary experiment is conducted to investigate three testing criteria from the viewpoint of investments. The results show that statement-coverage criterion performs best in gaining long-term yields; the short-term and medium-term yields of testing depend on the scale of programs and the number of faults they contain.
Submitted 3 August, ; originally announced August Aging research of the LAB-based liquid scintillator in stainless steel container. Aging is recognized as one of the main degradation mechanisms affecting the properties of liquid scintillator. LAB-based liquid scintillator aging experiments were carried out chen ying electromagnetic pump liquid different material of containers type and stainless steel and glass at two different temperature 40 and 25 degrees Celsius.
For the continuous liquid scintillator properties tests, the light yield and the absorption spectrum are nearly the same as that of the unaged one.
But the concentration of element Fe in the LAB-based liquid scintillator does not show a clear change. So the self aging has small effect on liquid scintillator, as well as the stainless steel impurity quenching.
Type and stainless steel can be used as LAB-based liquid scintillator vessel, transportation pipeline material. Submitted 3 September, ; originally announced September Exciton-polaritons chen ying electromagnetic pump liquid semiconductor microcavities generate fascinating effects such as long-range spatial coherence and Chen ying electromagnetic pump liquid Condensation BECwhich are attractive for their potential use in low threshold lasers, vortices and slowing light, etc.
However, currently most of exciton-polariton effects either occur at cryogenic temperature or rely on expensive cavity fabrication procedures. Further exploring new semiconductor microcavities with stronger exciton photon interaction strength is extensively needed.
With increasing pumping energy, exciton-photon coupling strength is weakened due to carrier screening effect, leading to occurrence of photonic lasing instead of polartion lasing. The demonstrated strong coupling between photons and excitons in perovskite microcavities would be helpful for development of high performance polariton-based incoherent and coherent light sources, nonlinear optics, and slow light applications. Submitted 10 August, ; originally announced September PlummerXuetao ZhuJiandong Guo.
Charge transfer and electron-phonon coupling EPC are proposed to be two important constituents associated with enhanced superconductivity in the single unit cell FeSe films on oxide surfaces. Using high-resolution electron energy loss spectroscopy combined with first-principles chen ying electromagnetic pump liquid, we have explored the lattice dynamics of ultrathin FeSe films grown on SrTiO3.
