Shaping of few-cycle laser pulses via a subwavelength structure

We theoretically investigate the propagation of few-cycle laser pulses in resonant two-level dense media with a sub- wavelength structure, which is described by the full Maxwell-Bloch equations without the frame of slowly varying envelope and rotating wave approximations. The input pulses can be shaped into shorter ones with a single or less than one optical cycle. The effect of the parameters of the subwavelength structure and laser pulses is studied. Our study shows that the media with a subwavelength structure can significantly shape the few-cycle pulses into a subcycle pulse, even for the case of chirp pulses as input fields. This suggests that such subwavelength structures have potential application in the shaping of few-cycle laser pulses.     

含克尔介质微波激射器的原子辐射率

建立了含克尔介质微波激射器(micromaser with Kerr medium)的基本量子原理,分析计算了处于不同方式(热原子和超冷原子状态)下的二能级原子沿z轴穿过处于相干态的含克尔介质微腔的原子辐射率,并着重讨论了克尔介质与单模辐射场作用的耦合强度χ、失谐量Δ和原子注入速率r对原子辐射概率的影响. 关键词： 含克尔介质微波激射器 热原子和超冷原子 原子辐射率     

Generation of NIulticomponent NIotional Coherent and Squeezed Coherent States of N Trapped Ions by a Dispersive Interaction

Following the recent proposal by Solano E et al. [Phys. Rev. Left. 87 (2001) 060402] a procedure is proposed to generate arbitrary discrete multicomponent motional coherent and squeezed coherent states of N trapped ions by additionally using a dispersive bichromatic interaction in a long-living and fast way. In this procedure, two lasers in the Raman configuration are tuned quasiresonant and resonant with N two-level ions under different conditions, respectively. Furthermore, we show how the idea can be used for the generation of two-mode SU(2) Schrdinger cat states for the vibrational motion of a single ion trapped in a two-dimensional harmonic potential.     

Possible Realization of Cluster States and Quantum Information Transfer in Cavity QED via Raman Transition

We present a scheme to generate cluster states with many scheme, no transfer of quantum information between the atoms in cavity QED via Raman transition. In this atoms and cavities is required, the cavity fields are only virtually excited and thus the cavity decay is suppressed during the generation of cluster states. The atoms are always populated in the two ground states. Therefore, the scheme is insensitive to the atomic spontaneous emission and cavity decay. We also show how to transfer quantum information from one atom to another.     

Efficient three-wave mixing in a three-level atomic medium with an assisting microwave driven field

The potential for nonlinear conversion between two laser pulses in a three-level V-type medium with assistance of an auxiliary microwave resonant radiation is studied. The results show that microwave driven field can lead to the parametric generation of a new laser pulse with high conversion efficiency when a weak pump laser pulse is applied.     

Photon statistics of the micromaser with a Kerr medium

We have established the master equation for the micromaser with a Kerr medium,we have studied the photon statics of the micromaser with a Kerr medium field and analysed the influence of the Kerr effect on the photon statistics,The influence of the Kerr effect on the photon statistics is different in two regimes,In the thermal-atom regime,the Kerr effect produces quantum noise,and decreases the mean photon number.In the ultracold-atom regime,with the increase of the nonlinear parameter of the Kerr medium,the stability of the mean photon number and the normalized variance enhances the mean photon number,and the normalized variance exhibits collapse-revival phenomena periodically,their resonance peaks become lower,and the photon statistics of more and more regions are sub-Poissonian.     

Efficient Scheme for Greenberger-Horne-Zeilinger State and Cluster State with Trapped Ions

We propose a scheme to generate the Greenberger-Horne-Zeilinger （GHZ） states and the cluster states of many trapped ions. In the scheme, the ion is illuminated by a single laser tuned to the first lower vibrational sideband. The scheme only requires resonant interactions. Thus the scheme is very simple and the quantum dynamics operation can be realized at a high speed, which is important in view of decoherence.     

与运动二能级原子作用的双模光场的量子特性

用全量子化理论,研究了与运动二能级原子相互作用的双模量子化光场的量子特性,分析了场模结构对平均光子数,单模二阶相干度,两模间的相关性的影响. 研究结果表明,随着场模结构参量的增大,平均光子数回复周期变短,振荡加剧,在崩塌区域内振荡出现分裂, 同时原子运动对光场的二阶相干性有明显的影响.     

运动的二能级原子与双模量子化腔场的相互作用

研究了一个微波激射器, 其腔内是单个运动的二能级原子与一双模量子化腔场的相互作用. 用修饰态来描述系统态矢量, 分析了在热原子状态下, 双模光场配制成不同的状态, 失谐量 对微波激射器的原子辐射率的影响. 关键词： 二能级原子 双模量子化腔场 原子辐射率     

Ultraslow Bright and Dark Solitons Using only a Pulsed Laser in a Cold Three-State Medium

We demonstrate the efficient generation of ultraslow bright and dark optical solitons in a lifetime-broadened three-level atomic medium by using only a low-intensity pulsed laser radiation. The proposed scheme may be useful, in principle, for the control technology of optical delay lines and optical buffers.