共查询到20条相似文献,搜索用时 15 毫秒
1.
Shi-Biao Zheng 《Optics Communications》2007,278(2):345-349
We propose an efficient scheme for realizing squeezing for a cavity mode. In the scheme, a collection of ladder-type three-level atoms are trapped in a cavity and driven by two classical fields. Under certain conditions, the cavity field deterministically evolves to a squeezed state. The scheme can also be used for conditional generation of superpositions of different squeezed vacuum states. 相似文献
2.
We present a scheme to generate a maximally entangled state of two three-level atoms in a cavity. The success or failure of the generation of the desired entangled state can be determined by detecting the polarization of the photon leaking out of the cavity. With the use of an automatic feedback, the success probability of the scheme can be made to approach unity. 相似文献
3.
Zong-Liang Liu Shao-Hua Li Chang-Yong Chen 《International Journal of Theoretical Physics》2009,48(8):2365-2371
A scheme for approximate and conditional teleportation of an unknown atomic state via dissipative two-photon interaction in
cavity QED is proposed. In our scheme, the dissipative two-photon interaction Jaynes-Cummings model is used to realize the
approximate and conditional teleportation. We investigate analytically the influence of the cavity mode decay on the teleportation
fidelity and show that the high fidelity teleportation can be implemented in dissipative case. Our scheme does not involve
the Bell-state measurement and an additional atom, only requiring two atoms and one single-mode cavity. The scheme may be
generalized to not only the teleportation of the state of a cavity mode to another mode by means of a single atom but also
the teleportation of the state of a trapped ion. 相似文献
4.
Polarization switching in a quasi-isotropic microchip Nd:YAG laser induced by optical feedback
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This paper demonstrates the influence of external optical
feedback on the polarization state of longitudinal modes in
quasi-isotropic microchip Nd:YAG lasers. Under optical feedback, the
polarization state of longitudinal modes in quasi-isotropic lasers
relies strongly on the intracavity anisotropy loss and mode
competition. When the intracavity anisotropy loss is small, external
optical feedback can cause polarization switching and strong mode
competition between two orthogonal linearly polarized eigenstates of
one laser longitudinal mode, which leads to the distortion of laser
intensity modulation waveform. The polarization switching is
independent of the initial external cavity length. By increasing the
intracavity anisotropy loss, one polarization eigenstate can be
suppressed and the laser works in single-polarization state. A
theoretical analysis based on the compound cavity model is
presented, which is in good agreement with the experimental results.
The results offer guidance to the development of laser feedback
interferometers. 相似文献
5.
We have studied theoretically and numerically the enhanced cooling of a V-type three-level atom in a high-finesse optical cavity and shown that the cooling rate can be increased by one order of magnitude over that of a two-level atom, and the momentum amplitude tends to a stationary state much smaller than that of a two-level atom. We have further shown that the cooling rate can be significantly improved by using feedback and a time-dependent pump. 相似文献
6.
研究利用基于量子跳跃的量子反馈控制来产生三个二能级原子之间稳定的纠缠.考虑三个二能级原子处于一个严重耗散的单模光腔中,分别讨论了反馈作用在一个原子上和反馈同时作用在三个原子上的情况.研究发现:当反馈作用在某个原子上时,基于量子跳跃的量子反馈能够保护另外两个原子的最大纠缠态.当反馈同时作用在三个原子上时,选择合适的参数可以得到两个基矢张开的无消相干子空间,并且利用量子轨迹蒙特卡罗波函数方法,得到一定初始条件下系统最终可以演化到这个子空间中三个原子之间的最大纠缠态. 相似文献
7.
提出了外腔延时反馈半导体激光器法拉第效应控制下的新激光系统, 构造出两种类型结构光路, 建立了法拉第效应控制下的延时负反馈、延时正反馈激光动力学物理模型, 研究了激光混沌控制与反控制等. 利用法拉第效应原理及磁致旋光性和系统特点, 调节控制光路中的光旋转角度和光延时间可实现双参数控制激光器, 控制激光到双周期、三周期及多周期, 使激光产生拍动等现象, 反控制激光周期到混沌等. 发现了以磁致旋光角分布的激光混沌控制与反控制区域. 并研究了激光混沌控制与周期控制的动态情况, 演示讨论了激光态的转化演变过程等. 相似文献
8.
9.
在一个双光反馈半导体激光混沌系统中,固定其中一个反馈腔镜(固定腔M1)的反馈延迟时间以及反馈强度,实验研究了另一个反馈腔镜(可变腔M2)的反馈延迟时间以及反馈强度对系统混沌输出的延时反馈特征的影响.研究结果表明:在可变腔M2与固定腔M1的反馈强度相等的条件下,改变M2的腔长,当其腔长约等于(但不能严格等于)M1的腔长或者腔长的一半时,系统将呈现较好地抑制延时反馈特征效果;当M
关键词:
半导体激光器
双光反馈
混沌输出
延时特征 相似文献
10.
F. Plastina F. Piperno 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》1999,5(3):411-415
We propose a simple method to obtain a superposition of coherent states on a circle, including Schr?dinger cat states as a
special case, via conditional measurement of the state of three level atoms interacting with a one mode cavity field. In the low amplitude
limit, very good approximation of Fock states can also be generated in this way.
Received: 8 October 1998 / Accepted: 30 October 1998 相似文献
11.
We show that strong squeezing and entanglement can be generated at the output of a cavity containing atoms interacting with two fields in a coherent population trapping situation, on account of a nonlinear Faraday effect experienced by the fields close to a dark-state resonance in a cavity. Moreover, the cavity provides a feedback mechanism allowing to reduce the quantum fluctuations of the ground state spin, resulting in strong steady state spin squeezing. 相似文献
12.
运用负值量子条件熵研究了双量子系统一类混合态的纠缠量度.给出了负值量子条件作为条件熵纠缠度的定义,证明了条件熵纠缠满足作为2×2系统一类混合纠缠态量度的四个基本条件.当双量子系统处于纯态时,条件熵纠缠度即为部分熵纠缠度.应用条件熵纠缠度研究了真空腔场中两全同二能级原子之间纯态和一类混合态纠缠的时间演化,比较了相同条件下两全同原子系统concurrence纠缠度的时间演化.结果表明,两纠缠度演化规律完全一致,验证了负值量子条件熵可以作为双量子系统纯态和一类混合态的纠缠量度.
关键词:
双量子系统
负值量子条件熵
条件熵纠缠度
混合态纠缠度 相似文献
13.
针对激光二极管阵列提出了"组合模"概念,计算了组合模的远场分布.每个组合模在远场的空间分布呈双瓣结构.基于激光二极管阵列组合模的远场分布特征,设计了离轴外腔反馈的激光二极管阵列.运用此装置所获得激光二极管阵列的远场分布有了明显变化.与自由运转的激光二极管阵列相比,离轴外腔反馈的激光二极管阵列远场宽度减少了4.3倍.在抽运电流为16 A时,测得输出激光的功率1.82 W,这相当于相同电流下自由运转激光器输出功率的79%.组合模理论不仅可以用来指导设计一维离轴外腔反馈激光二极管阵列,而且也可以用于设计二维离轴外腔反馈激光二极管阵列.二维离轴外腔反馈激光二极管阵列可以产生高功率,高光束质量输出的激光. 相似文献
14.
Internal stress in material detracts from its usefulness. In this Letter, a stress measurement instrument is reported. The instrument principle is based on a laser feedback effect where the polarization state of the laser with an anisotropic feedback cavity will flip between two orthogonal directions, while the feedback mirror is tuned by piezoelectric transducer sawtooth voltage. The position of polarization flipping in one period on curves reflects the birefringence or material internal stress of the feedback cavity. Hence, when a piece of internal stress material is placed in a feedback cavity, its internal stress can be measured by the polarization flipping position. The internal stress of the vacuum tube, Nd:YAG crystal, and GaN semiconductor are measured, which proved this instrument has very high precision. 相似文献
15.
实验利用双反馈半导体激光器获得了关联维数为3.8的高维混沌光.同时对比分析了双反馈与单反馈两种不同模式产生混沌的区别.结果表明:在反馈强度均为-26 dB时,双反馈产生混沌的关联维数高于单反馈产生混沌的关联维数2.6;双反馈可获得带宽为11 GHz的混沌光,为单反馈产生混沌带宽5.5 GHz的两倍.当双反馈的两个外腔长度不相等时,混沌的自相关曲线能很好的隐藏外腔长度信息,可提高混沌通信的保密性.
关键词:
双反馈
半导体激光器
混沌
带宽 相似文献
16.
F. Robert P. Besnard M. -L. Charès G. M. Stéphan 《Optical and Quantum Electronics》1995,27(9):805-811
We show that the light of a commercial vertical cavity surface-emitting laser with polarized optical feedback can be switched between two linear polarization eigenstates. The flip occurs when the feedback phase is scanned by either the external cavity length or the injection current. 相似文献
17.
A scheme is presented for generating entangled states of multiple
atoms in a cavity. In the scheme the atoms simultaneously interact
with a cavity mode, with the first atom driven by two classical
fields and the other atoms driven by a classical field. Our scheme
is valid even if the cavity decay rate is larger than the effective
coupling strength, which is important for experiment. The generation
of entangled states is conditional on the detection of a photon
decaying from the cavity and thus the fidelity of the entangled
state is insensitive to the detection inefficiency. Furthermore, the
scheme can be applied to the case with any number of atoms in
principle. 相似文献
18.
19.
利用超算符方法求解幅值损耗腔中两个∧型三能级原子与相干光场相互作用系统的主方程,并利用量子条件熵研究了两个初始为|Ψa(0)>和|Φa(0)>纠缠态的原子与光场作用过程中原子的纠缠演化特性.讨论了不同初始原子纠缠度,不同耗散系数以及不同平均光子数对两原子纠缠度的影响.结果表明:①当原子初始处于|Ψa(0)>类纠缠态时,其纠缠度随光场强度以及腔场衰减系数演化.当腔不存在耗散时,纠缠度呈周期性振荡;当腔存在耗散时,纠缠度呈衰减振荡并趋于稳定值;且光强越弱,其稳定值越大;衰减系数越大纠缠达到稳定值所需时间越短.②原子初始处于|Φa(0)>类纠缠态时,其纠缠度只与原子初始纠缠度有关,不随其他因素变化. 相似文献
20.
A scheme is proposed for generating entangled W states with four
cavity modes. In this scheme, we send a V-type three-level atom
through two identical two-mode cavities in succession. After the
atom exits from the second cavity, the four cavity modes are
prepared in the W state. On the other hand we can obtain
three-atom W states by sending three V-type three-level atoms
through a two-mode cavity in turn. The present scheme does not
require conditional measurement, and it is easily generalized to
preparing $2n$-mode W states and $n$-atom W states. 相似文献