共查询到20条相似文献,搜索用时 156 毫秒
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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。 相似文献
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利用电磁感应透明技术,在一维光晶格中相干驱动四能级Lambda模型冷原子系统,从而实现动力学可调谐电磁感应光子带隙结构。基于两邻近能级间的自发辐射相干(SGC)效应,通过控制耦合场从远共振到共振,使该原子系统实现从两个光子带隙转变为三个光子带隙的动态过程。当自发辐射相干效应不存在时,在探测场共振区域处探测光子被原子系统强烈吸收,因此感应光子带隙严重形变甚至无法形成。通过数值计算证明光子带隙结构的形成源自于自发辐射相干效应下探测场和耦合场之间的三阶交叉克尔(Kerr)非线性调制,并且通过控制耦合场的耦合方式,可以实现系统从两个光子带隙到三个光子带隙的动力学调控。 相似文献
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研究了双模SU(2)相干场与∧型三能级原子相互作用系统中场熵的演化特性。讨论了两场模与原子的耦合系数相对大小、单模场中光子数的最大可能值Ⅳ和描述两个场模光子平均数之比参数f的变化对场熵演化的影响。数值计算结果表明:两场模与原子的耦合强度近似相等时,场熵随时问作等幅周期性振荡;当两场模与原子的耦合系数相差较大时场熵演化出现崩塌和恢复现象,崩塌持续时间随两场模与原子的耦合系数之比l和两个场模光子平均数之比f增大而缩短,随单模场中光子数的最大可能值N增大而增大。 相似文献
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研究了双模SU(2)相干场与Λ型三能级原子相互作用系统中场熵的演化特性.讨论了两场模与原子的耦合系数相对大小、单模场中光子数的最大可能值Ⅳ和描述两个场模光子平均数之比参数ξ的变化对场熵演化的影响.数值计算结果表明:两场模与原子的耦合强度近似相等时,场熵随时间作等幅周期性振荡;当两场模与原子的耦合系数相差较大时场熵演化出现崩塌和恢复现象,崩塌持续时间随两场模与原子的耦合系数之比l和两个场模光子平均数之比ξ增大而缩短,随单模场中光子数的最大可能值N增大而增大. 相似文献
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用全量子理论研究二能级原子单模腔耦合系统,通过理论推导和数值计算得出系统的自发辐射光谱和平均粒子数密度.共振时腔与原子的发射光谱在强耦合与弱耦合区域有所不同,腔发射光谱分裂只出现于强耦合区域,而原子发射光谱由于腔感应透明效应在弱耦合区域出现了缺口.本文系统地研究了原子与腔在失谐时的发射光谱,在好腔机理(腔线宽小于原子线宽g)原子与腔即使在大失谐时腔发射出腔频率的光子,这给当前实验上困惑的特性提供了一个理论依据.为了给腔感应透明效应一个新的深入了解,还研究了原子与腔平均粒子数密度随时间的演化,以及平均粒子数密度与光强度之间的关系.
关键词:
自发辐射
强耦合
腔感应透明
好腔机理 相似文献
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《光学学报》2015,(7)
在非旋波近似下对双光子Jaynes-Cummings(J-C)模型与单模相干态光场相互作用的量子特性进行了精确求解。对双光子J-C模型与单光子J-C模型量子纠缠和原子布居数反转的演化特点进行了对比,讨论了平均光子数、光场与原子之间的耦合强度以及失谐对量子纠缠以及原子布居数反转的影响,数值计算的结果表明,随着光场与原子之间耦合强度的增大,量子纠缠的周期性逐渐消失,随着平均光子数的增加,纠缠达到较稳定的最大值所需时间逐渐增大。无论耦合强度、平均光子数还是失谐的增大,由非旋波项产生的虚光子效应逐渐增强,量子纠缠演化曲线和原子布居数反转的塌缩区出现小锯齿状振荡。 相似文献
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A simple method for calculating the linewidth of sources of stimulated coherent radiation caused by spontaneous noise and
thermal fluctuations has been proposed in the framework of the two-level model of the active medium. An expression for the
spectral width has been derived beyond the adiabatic approximation under an arbitrary relation between relaxation times in
a self-sustained oscillation system, taking into account a finite spectral band of spontaneous radiation. The result is applicable
for a wide class of coherent radiation sources. 相似文献
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We propose a scheme for implementing conditional quantum phase gates
for two four-state atoms trapped in a cavity. The two ground states
of the atoms are coupled through two Raman processes induced by the
cavity mode and two classical fields. Under certain conditions
nonresonant Raman processes lead to two-atom coupling and can
be used to produce conditional phase gates. The scheme is
insensitive to cavity decay, thermal photons, and atomic
spontaneous emission. The scheme does not require individual
addressing of the atoms. 相似文献
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A Fokker-Planck equation describing the coherent spontaneous emission from a system of 3-level atoms is derived using the atomic coherent states representation. The variables in this equation correspond directly to the number of atoms in the two excited states. The corresponding Langevin equations are discussed and their solutions for some special cases are presented. 相似文献
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We show that coherent spontaneous emission by a two-level atomic system in a Dicke state placed in a resonant cavity gives a non-classical radiation exhibiting photon-antibunching. It is assumed that the “effective” population of the ground state atoms is initially large compared to unity. 相似文献
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We investigate the entanglement between two atoms in an overdamped cavity injected with squeezed vacuum when these two atoms are initially prepared in coherent states. It is shown that the stationary entanglement exhibits a strong dependence on the initial state of the two atoms when the spontaneous emission rate of each atom is equal to the collective spontaneous emission rate, corresponding to the case where the two atoms are close together. It is found that the stationary entanglement of two atoms increases with decreasing effective atomic cooperativity parameter. The squeezed vacuum can enhance the entanglement of two atoms when the atoms are initially in coherent states. Valuably, this provides us with a feasible way to manipulate and control the entanglement, by changing the relative phases and the amplitudes of the polarized atoms and by varying the effective atomic cooperativity parameter of the system, even though the cavity is a bad one. When the spontaneous emission rate of each atom is not equal to the collective spontaneous emission rate, the steady-state entanglement of two atoms always maintains the same value, as the amplitudes of the polarized atoms varies. Moreover, the larger the degree of two-photon correlation, the stronger the steady-state entanglement between the atoms. 相似文献
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We analyze the dynamics of a dilute, trapped Bose-condensed atomic gas coupled to a diatomic molecular Bose gas by coherent Raman transitions. This system is shown to result in a new type of "superchemistry," in which giant collective oscillations between the atomic and the molecular gas can occur. The phenomenon is caused by stimulated emission of bosonic atoms or molecules into their condensate phases. 相似文献
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An exact solution of the problem of two two-level atoms with nondegenerate two-photon transitions and nondegenerate Raman transitions interacting with two-mode radiation field is presented. Asymptotic solutions for system state vectors are obtained in the approximation of large initial coherent fields. The atom-field entanglement is investigated on the basis of the reduced atomic entropy dynamics. The possibility of the system being initially in a pure disentangled state to revive into this state during the evolution process for both models is shown. Conditions and times of disentanglement are derived. 相似文献
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This review discusses the latest theoretical and experimental achievements in the resonant light pressure acting on the translational motion of atoms. Alongside with the effects due to the spontaneous light pressure (atomic deflection, velocity bunching, cooling), various manifestations of the effects of induced light pressure are considered in detail. This paper provides the theory and experiments of atoms scattering by a standing light wave under the conditions of coherent and non-coherent interaction, diffraction and interference of atomic beams. The problems where atomic motion along two trajectories and Landau-Zener transitions between them are essential, are studied. The kinetic phenomena (scattering, cooling, channeling) due to the motion of the particles exposed to gradient force and also friction and diffusion caused by spontaneous emission are considered. The influence of the recoil effect under spontaneous emission of atoms on non-linear polarization phenomena is discussed. 相似文献
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The dynamics of atom–field entanglement for two two-level atoms with degenerate two-photon transitions interacting with one-mode radiation field with taking into account the Stark shift is investigated. Asymptotic solutions for system state vectors are obtained in the approximation of large initial coherent fields. The atom–field entanglement is investigated also on the basis of the linear atomic entropy dynamics. The possibility of the system being initially in a pure disentangled state to revive into this state during the evolution process is shown. Conditions and times of disentanglement are derived. 相似文献
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1.IntroductionWiththerapiddevelopmentoftechniqueofthelasercoolingandtrappingofneutralatoms,theresearchesofatomicopticshavemaderemarkableprograseduringrecentyears,forexample,therealizationofBose-Einsteincondensation,thesuccessfulapplica-tionofatomiclensinlithographytechnique,andtheapplicationofatomicinterferometerinhighIyprecisemeasurementandsoon.AllofthesepredictthebrilliantprosPectofatomicoptics.EsPecially,thefieIdofatominterferometryhasenjoyedasurgeofinterestbecauseatomicinterferometerismu… 相似文献