光学孤子系统的微扰效应(英文)

考虑一个由微扰非线性Ｓｃｎｒａａｉｎｇｅｒ方程支配的光学孤子系统，在一级近似下，作者用直接微扰法得到孤子解及其存在条件，即微扰参数与孤子振幅间的一个关系。分析结果与早先的实验数据较好地一致。

其他

TN305 2003010762基于变芯径光纤的光学系统在光造型中的应用=Applicationof optical subsystem based on tapered optical fiber tostereolithography apparatus[刊,中]/杨继全(南京理工大学制造工程学院.江苏,南京(210094)),侯丽雅…//光学学报.-2002,22(4).-470-475光学系统采用变芯径光纤,可大幅度提高光的传输效率,增加光学子系统柔性。描述了光造型工作原理及其理论依据,在介绍所研制的光的成型系统光学子系统的基础上,阐述了紫外光源的选择与设计。

光计算、光计算机及器件

TP381 98042455基于能量最小的统计三级截值模型=A statisticaltrinary clipped model based on minimum energy[刊,中]/常胜江,申金媛,张延忻(南开大学国家教委光学信息技术科学开放实验室.天津(300071)),杨建文,金成海(南开大学现代光学研究所.天津(300071))∥光学学报.—1997,17(10).

Application of Laser Dispersion Method in Apparatus Combining H Atom Rydberg Tagging Time-of-Flight Technique with Vacuum Ultraviolet Free Electron Laser

Photodissociation of H2S in the VUV region plays an important role in the atmospheric chemistry and interstellar chemistry.To date,however,few studies have been focused on this topic.In this article,we have described a laser dispersion method applied in the apparatus combining the high-n H atom Rydberg tagging time-of-flight technique with the vacuum ultraviolet free electron laser(VUV FEL).The Lyman-αlaser beam(121.6 nm)used in the H-atom detection was generated by the difference frequency four-wave mixing schemes in a Kr/Ar gas cell.After passing through an off-axis biconvex LiF lens,the 121.6 nm beam was dispersed from the 212.6 nm and 845 nm beams due to the different deflection angles experienced by these laser beams at the surfaces of the biconvex lens.This method can eliminate the background signal from the 212.6 nm photolysis.Combined with the VUV FEL,photodissociation of H2S at 122.95 nm was studied successfully.The TOF spectrum was measured and the derived total kinetic energy release spectrum was displayed.The results suggest that the experimental setup is a powerful tool for investigating photodissociation dynamics of molecules in the VUV region which involves the H-atom elimination processes.

Channel Arrangement for optical communication subsystems with 12 parallel channels

This paper devoted to report the design and the achievement of an optical communication subsystem with 12 parallel channels in one chip.The system is capable of transmitting 10 Gbps bidirectional date over hundreds of meters.It can provide error detection and correction by using 8B/10B encoding and Cyclical Redundancy Checking (CRC) encoding when only single-channel fails.The design scheme has already passed the simulation in FPGA.This technique is useful to enhance the capability and the reliability of the very short reach (VSR) transmission systems.

Model for Interaction Between Photon and Cold Atom in QED Cavity

A model has been established for the interaction between a single-mode optical field and a 2-energy-level cold atom with exact analytic solutions given. The processes of momentum and energy exchanges between the optical field and the cold atom due to the interaction between them are discussed in detail, and a formula has been given for the variation of momentum and energy exchange volumes with time t in dress state while both the effects of photon recoil and Doppler effect are taken into consideration.

Multiformity of Optical Quantum Coherence Systems with Y and Inverted Y-type Schemes

Y and inverted Y-type four-level schemes for optical quantum coherence systems,which may be intuitivelyconsidered to be very simple,have not been studied intensively till now.In this paper,we present the multiformity ofthese two types of schemes by considering that they can be classified into nine possible level styles as the second-ordersub-schemes using laser fields.Further we point out the complexity of their more than one hundred realistic configurationsas the third-order four-level sub-schemes that may appear in the optical quantum coherence experiments.Throughoutthis paper we review which configurations have been studied in some research aspects and which ones not,accordingto our knowledge,in order to be propitious to next steps of theoretical and experimental investigations,especially forapplications in the fields of quantum optics,quantum information science,laser spectroscopy,and so on.

Anticontrol of Quantum Chaos in Hamiltonian Systems

We present a method of realizing anticontrol chaos in a quantum confined system consisting of N two-levelatoms within a cavity, using a time-delayed optic field. The delay time plays a construction and organization role forproducing temporal chaos, while the interaction between atoms and photons creates spatial chaos. The chaos is quitesensitive to small time delayed. The spectral decomposition of the Hamiltonian obtained by using projection methodologyreveals that evolution of the left eigenvectors shows quite complicated chaotic fashions. The method we proposed maybe easily tested in experiment, and provides a general method using a sort of driving optic field to achieve anticontrol ofchaos for quantum systems.

Comparative Analysis for Different Mathematical Models in Electron Optics

The comparative analysis of modem mathematical models for 3D problems in electron optics is presented. The new approach to solve the electron optics problems in three dimensions is presented. It is based on the principal ray method suggested by G. Grinberg in 1948. That perspective approach was not realized before for full three-dimensional electron optic systems, probably because of the complexity of its mathematical apparatus. We describe the analytical technique of the BEM （boundary element method） for the field evaluation, and 3rd order aberration expansion for the trajectory analysis. The first version of such computer code ＂OPTICS-3＂ and some results of numerical simulations with this code were presented.

Entanglement for a Bimodal Cavity Field Interacting with a Two-Level Atom

Negativity has been adopted to investigate the entanglement in a system composed of a two-level atom anda two-mode cavity field.Effects of Kerr-like medium and the number of photon inside the cavity on the entanglementare studied.Our results show that atomic initial state must be superposed,so that the two cavity field modes can beentangled.Moreover,we also conclude that the number of photon in the two cavity mode should be equal.The interactionbetween modes,namely,the Kerr effect,has a significant negative contribution.Note that the atom frequency and thecavity frequency have an indistinguishable effect,so a corresponding approximation has been made in this article.Theseresults may be useful for quantum information in optics systems.

Teleportation of an n-bit one-photon and vacuum entangled GHZ cavity-field state

A scheme for teleporting an arbitrary n-bit one-photon and vacuum entangled Greenberger-Horne-Zeilinger （GHZ） state is proposed. In this scheme, the maximum entanglement GHZ state is used as a quantum channel. We find a method of distinguishing four Bell states just by detecting the atomic states three times, which is irrelevant to the qubit number of the state to be teleported.

Quantum Mechanical Version for Bessel Beam's Propagation in ABCD Optical System

By introducing the entangled state representation and the two-mode Fresnel operator we provide quantum mechanical version for Bessel beam＇s classical propagation in ABCD optical system. This provides the opportunity of studying various classical Fresnel transformations in the context of quantum optics.

Heralded entanglement concentration for photon systems with linear-optical elements

We present two nonlocal entanglement concentration protocols(ECPs)to distill a subset of N-photon systems in a GreenbergerHorne-Zeilinger(GHZ)state or a W state from a set of photon systems in a partially entangled GHZ-like pure state or a lessentangled W-like state with known parameters,respectively.Our ECPs have some advantages.First,our ECPs work in a heralded way with linear-optical elements only,without the postselection based on nonlinear optics,far different from the previous ECPs.Second,they require only a copy of the less-entangled photon system in each round of the entanglement concentration process,not two copies,which decreases the difficulty of their implementation in experiment largely.Third,our ECPs avoid checking the photon number in the output modes of linear-optical elements with the sophisticated single-photon detectors.Moreover,all parties can operate the process for concentration simultaneously and independently,which leads to flexible operations and improves the performance greatly in experiment.These advantages make our ECPs useful in practical applications in long-distance quantum communication network.

Dynamics and entanglement of a membrane-in-the-middle optomechanical system in the extremely-large-amplitude regime

The study of optomechanical systems has attracted much attention, most of which are concentrated in the physics in the smallamplitude regime. While in this article, we focus on optomechanics in the extremely-large-amplitude regime and consider both classical and quantum dynamics. Firstly, we study classical dynamics in a membrane-in-the-middle optomechanical system in which a partially reflecting and flexible membrane is suspended inside an optical cavity. We show that the membrane can present self-sustained oscillations with limit cycles in the shape of sawtooth-edged ellipses and exhibit dynamical multistability. Then, we study the dynamics of the quantum fluctuations around the classical orbits. By using the logarithmic negativity, we calculate the evolution of the quantum entanglement between the optical cavity mode and the membrane during the mechanical oscillation. We show that there is some synchronism between the classical dynamical process and the evolution of the quantum entanglement.

Concentrating partially entangledW-class states on nonlocal atoms using low-Q optical cavity and linear optical elements

Entanglement plays an important role in quantum information science, especially in quantum communications. Here we present an efficient entanglement concentration protocol(ECP) for nonlocal atom systems in the partially entangled W-class states, using the single-photon input-output process regarding low-Q cavity and linear optical elements. Compared with previously published ECPs for the concentration of non-maximally entangled atomic states, our protocol is much simpler and more efficient as it employs the Faraday rotation in cavity quantum electrodynamics(QED) and the parameter-splitting method. The Faraday rotation requires the cavity with low-Q factor and weak coupling to the atom, which makes the requirement for entanglement concentration much less stringent than the previous methods, and achievable with current cavity QED techniques. The parameter-splitting method resorts to linear-optical elements only. This ECP has high efficiency and fidelity in realistic experiments, and some imperfections during the experiment can be avoided efficiently with currently available techniques.

Roles of Atomic Injection Rate and External Magnetic Field on Optical Properties of Elliptical Polarized Probe Light

In this paper we investigate the optical properties of an open four-level tripod atomic system driven by an elliptically polarized probe field in the presence of the external magnetic field and compare its properties with the corresponding closed system.Our result reveals that absorption,dispersion and group velocity of probe field can be manipulated by adjusting the phase difference between the two circularly polarized components of a single coherent field,magnetic field and cavity parameters i.e.the atomic exit rate from cavity and atomic injection rates.We show that the system can exhibit multiple electromagnetically induced transparency windows in the presence of the external magnetic field.The numerical result shows that the probe field in the open system can be amplified by appropriate choice of cavity parameters,while in the closed system with introduce appropriate phase difference between fields the probe field can be enhanced.Also it is shown that the group velocity of light pulse can be controlled by external magnetic field,relative phase of applied fields and cavity parameters.By changing the parameters the group velocity of light pulse changes from subluminal to superluminal light propagation and vice versa.

Optical applications of quantum dots in biological system

This review presents a simple introduction on the unique properties and general synthesis of quantum dots (QDs) in which we lay emphasis on the optical applications in the biological system. The detection of biological molecules such as DNA, protein and enzyme, the cell-based analysis and in vivo animal imaging are mainly discussed.

Optomechanically-induced-transparency cooling of massive mechanical resonators to the quantum ground state

Ground state cooling of massive mechanical objects remains a difficult task restricted by the unresolved mechanical sidebands. We propose an optomechanically-induced-transparency cooling scheme to achieve ground state cooling of mechanical motion without the resolved sideband condition in a pure optomechanical system with two mechanical modes coupled to the same optical cavity mode. We show that ground state cooling is achievable for sideband resolution ωm/k as low as - 0.003. This provides a new route for quantum manipulation of massive macroscopic devices and high-precision measurements.

Intramedullary devices in the management of Judet III and IV paediatric radial neck fractures

Purpose： The aim of this study is to discuss the results of different intramedullary devices used in the management of paediatric radial neck fractures and to suggest methods to avoid the pitfalls of the technique. Methods： Thirty patients with isolated Judet III and IV fractures were included in this prospective study. Judet I and II fractures and radial neck fractures associated with other injuries were excluded. The final results were graded using the Metaizeau functional scoring system and Oxford Elbow Score. Results： The functional result was good to excellent in 24 of 30 cases （80%）. The mean Oxford Elbow Score was 44.32. The mean follow-up was 40.11 months. The complications seen were radiocapitellar joint penetration - 6 cases at mean 4.87 weeks, redisplacement - 6, radial epiphyseal sclerosis - 5, and heterotopic ossification 1 case. Conclusion： lntramedullary K wires may result in radiocapitellar joint penetration. Titanium Elastic Nail System should not be used as purely fixation devices as they may not prevent redisplacement. Regular follow-up until at least 6 weeks is essential. Patients who have a Judet IV fracture and need open reduction should be given a guarded prognosis. The paper highlights the pitfalls of the technique and makes recommendations regarding the type of implant, follow-up and patient counselling in Judet IV fractures.

Experimental demonstration of photonic quantum ratchet

We create a potential for light with a phase mirror and then experimentally realize a photonic quantum ratchet in an all-optical system, in which ratchet effects can be observed with the naked eye up to more than 22 steps, and quantum resonance can be demonstrated. Our method also provides a new means to simulate quantum particles with classical light, and it can be applied to investigate many other quantum phenomena.