腔长对Er:YAG 2.94μm激光输出的影响

本文从实验和理论上研究了Ｅｒ：ＹＡＧ激光器的谐振腔腔长对泵浦阈值和斜率效率的影响．导出了它们之间的数学表达式，说明了腔长影响的主要因素是腔内水汽对２．９４μｍ激光的强烈吸收．

环形腔中非线性周期结构介质的双稳态和光限

研究了环形腔中的非线性周期结构介质的光学双稳态和光限现象，建立了输入光强与输出光强关系的表达式。

An Improved On-Chip CMOS Astable Multivibrator

An improved on-chip CMOS astable multivibrator is proposed, which overcomes the shortcomings of the traditional one that the signal duty-cycle is depending on model parameters, and generates stable clock signal with duty-cycle equaling 50%. The latch-up effect has been prevented on the improved circuit. It is extremely important that all the excellent performances of the improved astable multivibrator have been achieved with a dynamic power consumption equaling its predecessor one. The advantage of the structure has been verified by SPICE simulation.

新型直线振荡电机建模与动态特性实验

针对提出的直接驱动液压伺服泵新原理,设计了一种短行程永磁直流直线振荡电机,阐述了基于最小磁阻理论的电机工作原理,采用一种哈尔巴赫磁极阵列空心动子设计结构,用于提高电机动态响应能力,并利于谐振弹簧的安装.利用Matlab/Simulink建立了电机的集中参数数学模型并给出传递函数,通过正弦电压扫频激励,获取了电机空载下的电流频率特性以及恒定负载下的效率频率特性.基于电机模型设计了电流环与位置环双闭环控制结构,用于提高电流的频响与位置跟踪能力.最后对设计的电机进行了空载谐振与闭环动态实验研究,实验与分析仿真结果基本吻合,验证了电机模型与闭环控制结构的有效性.

A Hierarchical-Equation-of-Motion Based Semiclassical Approach to Quantum Dissipation

We present a semiclassical （SC） approach for quantum dissipative dynamics, constructed on basis of the hierarchical-equation-of-motion （HEOM） formalism. The dynamical components considered in the developed SC-HEOM are wavepackets＇ phase-space moments of not only the primary reduced system density operator but also the auxiliary density operators （ADOs） of HEOM. It is a highly numerically efficient method, meanwhile taking into account the high-order effcts of system-bath couplings. The SC-HEOM methodology is exemplified in this work on the hierarchical quantum master equation [J. Chem. Phys. 131, 214111 （2009）] and numerically demonstrated on linear spectra of anharmonic oscillators.

Notes on Application of WKB Method

The notes here presented are of the modifications introduced in the application of WKB method.Theproblems of two-and three-dimensional harmonic oscillator potential are revisited by WKB and the new formulationof quantization rule respectively.It is found that the energy spectrum of the radial harmonic oscillator,which isreproduced exactly by the standard WKB method with the Langer modification,is also reproduced exactly without theLanger modification via the new quantization rule approach.An alternative way to obtain the non-integral Maslov indexfor three-dimensional harmonic oscillator is proposed.

Absolute Orientation of Molecules with Competing Hydrophilic Head Groups at the Air/Water Interface Probed with Sum Frequency Generation Vibrational Spectroscopy

The constructive or destructive spectral interference between the molecular groups oriented up and down at the interface in the sum-frequency generation （SFG） spectra provides a direct measurement of the absolute orientation of these molecular groups. This simple approach can be employed to interrogate absolute molecular orientations other than using the complex absolute phase measurement in the SFG studies. We used the -CN group in the p-cyanophenol （PCP） molecule as the internal phase standard, and we measured the phases of the SFG fields of the -CN groups in the 3,5-dimethyl-4-hydroxy-benzonitrile （35DMHBN） and 2,6-dimethyl-4-hydroxy-benzonitrile （26DMHBN） at the air/water interface by measuring the SFG spectra of the aqueous surfaces of the mixtures of the PCP, 35DMHBN, and 26DMHBN solutions. The results showed that the 35DMHBN had its -CN group pointing into the aqueous phase; while the 26DMHBN, similar to the PCP, had its -CN group pointing away from the aqueous phase. The tilt angles of the -CN group for both the 35DMHBN and 26DMHBN molecules at the air/water interface were around 25°-45° from the interface normal. These results provided insights on the understanding of the detailed balance of the competing factors, such as solvation of the polar head groups, hydrogen bonding and hydrophobic effects, etc., on influencing the absolute molecular orientation at the air/water interface.

Approximate Teleportation of an Unknown Atomic-Entangled State with Dissipative Atom-Cavity Resonant Jaynes-Cummings Model

We propose a scheme for approximately and conditionally teleporting an unknown atomic-entangled state in dissipative cavity QED. It is the further development of the scheme of [Phys. Rev. A 69 （2004） 064302], where the cavity mode decay has not been considered and the state teleportated is an unknown atomic state. In this paper, we investigate the influence of the decay on the approximate and conditional teleportation of the unknown atomic-entangled state, which is different from that teleportated in [Phys. Rev. A 69 （2004） 064302] and then give the fidelity of the teleportation, which depends on the cavity mode decay. The scheme may be generalized to not only the teleportation of the cavity-mode-entangled-state by means of a single atom but also the teleportation of the unknown trapped-ionentangled-state in a linear ion trap.

Cavity QED Scheme for Realizing Entanglement Swapping

A new scheme is proposed for realizing entanglement swapping in cavity QED. The scheme is based on the resonant interaction of two-mode cavity with ∧-type three-level atom, and it involves only a single measurement. In the scheme, the output state after swapping is exactly the maximally entangled state in principle, thus it is prior to the previous one, in which the output state is just approximate. Calculations indicate that our scheme is less influenced by an error.

原子激光器的新进展

1960年,西奥多·梅曼(Theodore Maiman)利用人工合成的红宝石晶体作为激活物质并利用闪光灯通过光泵浦实现粒子数反转,研制成功了第一台脉冲光学激光器.六个月之后,阿里·贾范(Ali Javan)发明了第一台连续光学激光器(在他的氦-氖激光器中,被电激励到激发态的氦原子与基态氖原子的碰撞产生了连续激光输出所需要的粒子数反转).仅仅一天之后,这种激光器就被用于电话信号传送.如今,其应用范围涵盖从精密光谱学到材料处理的众多领域.

Unified Treatment of Screening Coulomb and Anharmonic Oscillator Potentials in Arbitrary Dimensions

A mapping is obtained relating radial screened Coulomb systems with low screening parameters to radial anharmonic oscillators in N-dimensional space. Using the formalism of supersymmetric quantum mechanics, it is shown that exact solutions of these potentials exist when the parameters satisfy certain constraints.

Forced Time-Dependent Harmonic Oscillators in Non-Commutative Space

For the time-dependent harmonic oscillator and generalized harmonic oscillator with or without external forces in non-commutative space, wave functions, and geometric phases are derived using the Lewis-Riesenfeld invariant. Coherent states are obtedned as the ground state of the forced system. Quantum fluctuations are calculated too. It is seen that geometric phases and quantum fluctuations are greatly affected by the non-commutativity of the space.

On High Brightness Temperature of Pulsar Giant Pulses

A wide range of events observed at the giant pulses （high energy density, observed localization of giant pulses GPs relative to the average pulse, fine structure of GPs with duration up to some nanoseconds, observed circular polarization of GPs, correlation between the GP phase and the phase of the hard pulsar emission X-ray and gamma） can be explained from the viewpoint that the internal polar gap is a cavity-resonator stimulated by discharges and radiating through the breaks in the magnetosphere. The new results in this field [the electromagnetic （era） waves generation in the gap in the process of longitudinal acceleration in the electric field vanishing on the star surface, high frequency break in the spectrum as a result of switching off this generation, formation in this process a power-low spectrum with a high frequency （hf） break, the possibility determination of pulsar magnetic field by the hf break position, the difference between main pulse and inter pulse mechanism generation, quantization of em tornado rotation in the gap and appearance of the bands in the inter pulse spectrum, influence the high energy density in the gap on pair generation and position of the dead line in pulsars] are added in the intermediate epilogue.

Strategies for h-Adaptive Refinement for a Finite Element Treatment of Harmonic Oscillator Schrodinger Eigenproblem

A Schrodinger eigenvalue problem is solved for the 219 quantum simple harmonic oscillator using a finite element discretization of real space within which elements are adaptively spatially refined. We compare two competing methods of adaptively discretizing the real-space grid on which computations are performed without modifying the standard polynomial basis-set traditionally used in finite element interpolations; namely, （i） an application of the Kelly error estimator, and （ii） a refinement based on the local potential level. When the performance of these methods are compared to standard uniform global refinement, we find that they significantly improve the total time spent in the eigensolver.

Dynamics of Light in Teleparallel Bianchi-Type I Universe

In the present study, using the Fourier analysis method and considering the Bianchi-type I spacetime, we investigate the dynamics of photon in the torsion gravity, and show that the free-space Maxwell equations give the same results. Furthermore, we also discuss the harmonic oscillator behavior of the solutions.

Correlated spectrum of distant semiconductor qubits coupled by microwave photons

We develop a new spectroscopic method to quickly and intuitively characterize the coupling of two microwave-photon-coupled semiconductor qubits via a high-impedance resonator.Highly distinctive and unique geometric patterns are revealed as we tune the qubit tunnel couplings relative to the frequency of the mediating photons.These patterns are in excellent agreement with a simulation using the Tavis-Cummings model,and allow us to readily identify different parameter regimes for both qubits in the detuning space.This method could potentially be an important component in the overall spectroscopic toolbox for quickly characterizing certain collective properties of multiple cavity quantum electrodynamics(QED)coupled qubits.