真空场注入三态叠加MFSS光场广义电场的等幂偶次Y压缩

对真空场注入三态叠加MFSS(多模泛函叠加态)光场|ψ_0~(3)〉q广义电场分量的等幂次偶次振幅压缩特性进行了详细研究,分析了光场经典强度、经典振幅和经典相位的任意空间分布特征、以及真空场注入对该光场的广义电场分量的等幂偶次Y压缩效应其压缩幅度和压缩量的影响。结果发现:导致态|ψ_0~(3)〉q的广义电场分量存在等幂偶次2m次方Y压缩效应的根本原因在于模间的量子干涉效应、态间的量子干涉效应以及模间和态间的量子纠缠效应;真空场注入可使该光场广义电场分量的2m次方Y压缩效应增强、压缩幅度增大、压缩程度加深。     

压缩真空态光场在光纤中传输特性的研究

本文利用简并光学参量振荡器实验制备了光通信波段1.5μm压缩真空态光场,压缩度为(5.03±0.13) d B。将已制备的1.5μm压缩真空态光场和同频率本地振荡光采用偏振复用的方式耦合注入单模光纤中进行传输,在理论和实验上研究了压缩真空态光场在光纤信道传输过程中经典和量子特性的演化,并讨论了本地振荡光在光纤信道中引起的声导波布里渊散射对传输过程的压缩真空态光场影响。实验测量了1.5μm压缩真空态光场在单模光纤中传输距离为8 km时,压缩度为0.14 dB,压缩特性仍得到保持。该研究为实现基于光纤的城域量子信息网络等奠定基础。     

探测器对量子增强马赫-曾德尔干涉仪相位测量灵敏度的影响

研究了强度差测量方案下,探测器量子效率对光子数态、关联数态、压缩真空态三种量子光源注入的马赫-曾德尔干涉仪相位测量灵敏度的影响.获得了相位测量灵敏度与效率的定量关系,比较了探测效率对不同量子态注入的干涉仪相位灵敏度的影响.研究表明：光子数态注入时,相位测量灵敏度始终不能超越标准量子极限;关联数态注入时,无论多大的光子数,要获得相位测量的量子增强,探测效率不得小于75%;对于压缩真空态,只要有压缩存在就可以获得一定的相位测量的量子增强;关联数态、压缩真空态的注入,相位灵敏度皆随探测效率的增大而不同程度的提高,且压缩真空态比关联数态具有更好的量子增强效果.给出了在量子增强的精密测量实验中对探测效率的要求,并结合实际应用说明了探测效率的提高有助于提高干涉仪探测的灵敏度.     

弱光反馈下正交时变光注入VCSEL的双稳特性研究

基于垂直腔面发射激光器(VCSEL)的自旋反转模型(SFM),研究了弱光反馈下正交时变光注入VCSEL的双稳特性。研究结果表明,当副激光器(S-VCSEL)受到主激光器(M-VCSEL)正交时变光注入时,弱光反馈的引入不改变正交时变光注入VCSEL的双稳宽度随光注入扫描速率增大而增大的性质;对于确定的光注入扫描速率,随着反馈强度的增大,双稳宽度将变窄;当M-VCSEL与S-VCSEL之间存在频率失谐Δν(等于νm-νs,νm、νs分别为主、副激光器自由运行时的频率)时,随着Δν从负值逐渐增加到正值,双稳宽度总体呈现先减小后增大的趋势,无反馈时在负频区域双稳环宽度呈现的较大波动在引入光反馈后可得到一定程度的抑制。     

一个压缩真空注入的光学双稳态的线性稳定性分析

应用线性稳定性分析的方法对一个压缩真空注入的光学双稳态系统进行了分析,给出了这个输入输出系统稳定性存在的微观参量条件。     

劣腔内二能级原子的双光子共振荧光光谱

研究了劣腔内二能级原子与单模腔场的双光子相互作用，腔内原子受外加固相干光场驱动，并向一般真空态自发辐射，通过腔镜内腔内注入压缩真空态光场，使腔模向压缩真空态光场衰减，本文利用劣腔近似条件得到原子约化密度算符主方程，在此基础上讨论了二能级原子的双光子共振荧光光谱。     

真空场注入4SMES光场广义电场的4m+2次和压缩

根据量子力学中态的线性叠加原理,构造了由多模真空态、多模相干态、多模相干态的相反态和多模虚相干态的线性叠加所组成的真空场注入四态叠加多模纠缠态(即4SMES)光场.利用多模压缩态理论研究了上述光场中广义电场分量的等幂次高次和压缩特性.结果发现:真空场注入4SMES光场是一种典型的四态叠加多模非经典光场;在一定条件下,该光场的广义电场分量可呈现出周期性变化的广义非线性等幂4m+2次和压缩效应.     

真空场注入4SMES光场广义电场的4m+2次和压缩

根据量子力学中态的线性叠加原理,构造了由多模真空态、多模相干态、多模相干态的相反态和多模虚相干态的线性叠加所组成的真空场注入四态叠加多模纠缠态(即4SMES)光场.利用多模压缩态理论研究了上述光场中广义电场分量的等幂次高次和压缩特性.结果发现:真空场注入4SMES光场是一种典型的四态叠加多模非经典光场;在一定条件下,该光场的广义电场分量可呈现出周期性变化的广义非线性等幂4m+2次和压缩效应.     

在亚泊松泵浦统计和压缩真空条件下多单光子关联辐射光子双稳态

证明了亚泊松泵浦及原子的相干性可使多单光子双稳态的光场噪声降低，但不能产生光场的压缩效应，若向腔中注入压缩真空，可以双稳态的上支产生几乎完全挑子数压缩效应，同时还证明，双稳态临界合作与原子相干性及集居数都有关。     

对腔外原子操作时腔内原子的发射性质

考虑初始处于W态的三个双能级原子，将其中两个分别注入处于真空态的两个腔中，发生共振相互作用。通过对腔外原子进行适当的旋转及测量，可使腔场发射双模压缩光，并且当旋转角度发生变化时，压缩的程度也会发生变化。     

OPTICAL BISTABILITY IN V MEDIUM BY SQUEEZED VACUUM INPUT

We discuss the optical bistable behavior of a system of N V-type three-level atoms pumped by a coherent input field and coupled to a squeezed vacuum field by treating the optical hist ability of such a system as an input-output problem. It is shown that bistability can be realized due to the squeezed vacuum input.     

Optical bistability of a composite system induced by a broadband squeezed vacuum

A composite system consisting of a degenerate optical parametric oscillator （DOPO） and N two-level atoms interacting with a broadband squeezed vacuum （SV） centred at frequency cas and an input monochromatic pumping field with a frequency ωp is analysed. The corresponding explicit analytical steady-state solutions in the central mode ωp = ωs are derived, and the result displays optical bistability （OB）. In addition, the influence of the broadband SV on the bistable behaviour is analysed in detail.     

Multiple Effective Two-photon Correlated-emission Optical Bistability with Injected Squeezed Vacuum

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Bistable behaviour in squeezed vacua: I. Stationary analysis

A time-independent theoretical and numerical analysis of an optical bistable model of two-level atoms in a ring cavity, driven by a coherent field and in contact with a squeezed vacuum field is presented in the two cases of absorptive and dispersive optical bistability (OB). In the former case, a suitable choice of the phase of the squeezed vacuum field reduces the threshold for OB to occur compared with the normal vacuum case. In the latter case, regions of OB are identified as one or two disconnected simple closed curves depending on the cooperation parameter [0pt] : is the maximum possible value of the critical value of C at fixed values of the squeezed vacuum field parameters. Phase switching effects between different (output) states of the system is investigated in detail. In the absorptive case, one- or two-way optical switching is possible depending on [0pt] . We also present results which demonstrate more complicated switching behaviour in the dispersive case. Received 12 March 1999 and Received in final form 20 August 1999     

Electro-Optic Switching in a Double Quantum Dot Injected with a Squeezed Vacuum Field

Journal of Russian Laser Research - Optical bistability (OB) is theoretically examined for a double quantum dot (QD) system placed in a ring cavity that is injected with a squeezed vacuum (SV)...     

Critical slowing down in a bistable model with squeezed vacuum environment

Critical slowing down effect in a bistable model of a two-level atomic medium in a ring cavity and in contact with squeezed vacuum field is examined within the mean field approximations in the high-, low- and arbitrary-Q cavity cases. Depending on the squeezed vacuum field phase parameter, the time response to linear perturbation of the incident field near the swtiching-on point can be enhanced or reduced compared with the normal vacuum case. In the low-Q cavity case with atomic collisional broadening switching time is both increased and become insensitive to the phase of the squeezed vacuum field. Analytical expressions are given and analysed for the critical (extermal) values of the incident field. In the high-Q cavity, Gaussian field feature causes lesser-steep transition between the stable states in both the normal and squeezed vacuum cases.Received: 25 April 2004, Published online: 24 August 2004PACS: 42.65.Pc Optical bistability, multistability, and switching, including local field effects - 42.65.-k Nonlinear optics     

Enhanced phase sensitivity of an SU(1,1) interferometer with displaced squeezed vacuum light

We study the phase sensitivity of an SU(1,1) interferometer with two input beams in the displaced squeezed vacuum state and the coherent state, respectively. We find that there exists an optimal squeezing fraction of the displaced squeezed vacuum state that optimizes the phase sensitivity. We also examine the effects of some factors, including the loss, mean photon number of the input beams and amplitude gain of the optical parameter amplifiers, on the optimal squeezing fraction so that we can choose the optimal values to enhance the phase sensitivity.     

高灵敏度的量子迈克耳孙干涉仪

迈克耳孙干涉仪不仅可以用来研究物理学的基本问题,而且能够用于精密测量,比如引力波信号的测量.因此,构建高灵敏度的迈克耳孙干涉仪是实现微弱信号测量的关键.目前,人们利用压缩态可以降低迈克耳孙干涉仪的噪声;通过光学四波混频过程能够放大马赫·曾德尔干涉仪中的相位信号,从而提高干涉仪的信噪比和灵敏度.本文研究了一种用于高灵敏度相位测量的量子迈克耳孙干涉仪.在迈克耳孙干涉仪中,利用非简并光学参量放大器取代干涉仪中的线性光学分束器;并且将压缩态注入干涉仪的真空通道,可以得到高信噪比和高灵敏度的干涉仪.由于存在不可避免的光学损耗,分析了迈克耳孙干涉仪内部和外部的损耗对相位测量灵敏度的影响.通过理论计算研究了干涉仪的相位测量灵敏度随系统参数的变化关系,得到了高灵敏度的相位测量量子迈克耳孙干涉仪的实现条件,为用于精密测量的干涉仪的设计提供了直接参考.