共查询到20条相似文献,搜索用时 15 毫秒
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在旋波、慢变振幅近似下,求解考虑了驱动场相位扩散后的系统密度矩阵运动方程,并给出了这个三能级梯型系统稳态线性解析解.利用得到的稳态线性解析解分析驱动场相位扩散是如何影响该系统输出无反转激光的.对稳态线性解析解数值计算的结果显示:由于驱动场相位扩散会导致无反转激光增益减小;即使由于驱动场相位扩散引起的线宽足够大,在该系统中仍能够获得无反转激光;线宽往往是破坏无反转激光产生和折射率的提高;因驱动场相位扩散导致无反转激光增益的减小,并不是总能够通过增大驱动场的Rabi频率得到补偿. 相似文献
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提出开放的四能级双驱动场无反转激光系统的理论模型,由电偶极和旋转波近似得到其密度矩阵方程,讨论无反转激光产生的物理机制,利用数值计算结果分析探测场和驱动场失谐对系统无反转激光增益和粒子数差的影响. 相似文献
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<正>We study the lasing without inversion in a four-level diamond configuration in the case of incoherent pumping field within the framework of the bare-state basis.With the strong fields limit,we obtain the approximate steady-state solution,and discuss the dependence of population distribution and system gain on probe detuning and auxiliary field Rabi frequency. 相似文献
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Large Enhancement of Probe Amplification with Population Inversion in a Four-Level Atomic System with Vacuum-Induced Coherence 总被引:1,自引:0,他引:1
In this paper, we discuss and analyze theoretically probe
absorption-amplification response in a four-level coherent atomic
system with vacuum-induced coherence via changing the sign
of the parameter f, with f denoting the ratio of a pair of dipole moments associated with a doublet of closely upper hyperfine sublevels. We find that the amplitude of the probe
amplification for the case f=-1 can be about one order of
magnitude larger than that achievable for the case f=1. In addition, with respect to the case f=-1 the probe amplification
can be maintained all the time with weak incoherent pumping for a
wide range of the probe detuning. 相似文献
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提出了一个由两个弱探测场和两个强耦合场驱动的四能级双V型原子系统, 研究发现在四波混频共振条件下, 两探测场均可被放大而无须粒子数反转. 值得注意的是, 由于所选择的激发态为超精细结构的两个近能级, 这里必须考虑自发辐射相干效应的影响. 与不考虑自发辐射相干相比, 同样参数条件下探测场的增益得到大幅度提高.而且, 探测场增益对相位非常敏感, 即增益-吸收线型受相位周期性调制, 同时也受两个偶极矩之间夹角θ制约. 此外还分析了相干抽运场 (强耦合场)的失谐对增益谱线产生的影响.
关键词:
无粒子数反转激光
四波混频
自发辐射相干 相似文献
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建立微波驱动基态精细结构跃迁的Λ型三能级系统,研究基于自发辐射相干控制的电磁感应透明诱导无反转光放大效应.微波场作用于基态精细结构能级之间,产生3个透明窗口,利用适当角度的自发辐射相干效应与电磁感应透明耦合,实现透明向光放大的转化.结果表明,透明转化为光放大时,激发态与基态能级之间以及两个基态能级之间均不出现粒子数反转,但在产生光放大的过程中必须经历两个基态能级出现粒子数反转的状态.调节微波场的频率失谐量可以改变基态能级上的粒子数分布,有利于无反转光放大的产生. 相似文献
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在封闭的简单四能级原子系统模型的基础上提出了开放的四能级原子系统模型.通过在电偶极和旋转波近似下,解此系统的半经典密度矩阵运动方程得其稳态线性解析解.对该稳态解的数值模拟显示:随着驱动场的Rabi频率的连续增加系统会发生由输出的无粒子数反转激光到输出粒子数反转激光的转变;随着系统退出速率或者注入速率比的连续增大,系统会发生由输出的粒子数反转激光到输出无粒子数反转激光的转变;该系统能获得无吸收高色散;在稳态,探测激光上下能级粒子数差随探测场失谐的变化曲线呈弱矩形波. 相似文献
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从理论上分析了无反转自由电子激光器的原理,并提出了一个新的无反转自由电子激光器的实现方案。通过增加两块电子反射镜,使电子受激辐射的几率幅相干叠加,得到的增益两倍于原有的方案。 相似文献
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Influence of Doppler broadening and spontaneously generated coherence on propagation effect in a quasi lambda-type four-level system 下载免费PDF全文
In this paper we study influences of Doppler broadening, spontaneously generated coherence, and other system parameters on propagation effect in a quasi lambda-type four-level atomic system. It is shown that when the Doppler broadening is present, generally speaking, the values of gain and intensity of lasing without inversion (i.e. the probe field) in the co-propagating probe and driving fields case are much larger than those in the counter-propagating case; considerably larger gain and intensity of lasing without inversion than those without the Doppler broadening can be obtained by choosing appropriate values of the Doppler broadening width and spontaneously generated coherence strength. The gain and intensity of lasing without inversion increase with the increase of spontaneously generated coherence strength; when spontaneously generated coherence is present, much larger gain and intensity of lasing without inversion than those in the case without spontaneously generated coherence can be obtained. Choosing suitable values of the probe detuning, Rabi frequencies of the driving and pump fields at the entrance of the medium also can remarkably enhance the gain and intensity of lasing without inversion. 相似文献
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The topological expression of the reduced quantum trajectory is given by using C-mapping topological current theory. The topological expression is used in study of the coherence and the decoherence. We find the expression of vorticity for decoherence has a similar form as that for coherence. A topological reason leading to the decoherence is given and a new parameter is defined to indicate the coherence degree. The parameter is different from the damping factor because it relates to the topological structure of the reduced quantum trajectory. 相似文献
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The topological expression of the reduced quantum trajectory is given by using ø-mapping topological current theory. The topological expression is used in study of the coherence and the decoherence. We find the expression of vorticity for decoherence has a similar form as that for coherence. Atopological reason leading to the decoherence is given and a new parameter is defined to indicate the coherence degree. The parameter is different from the damping factor because it relates to the topological structure of the reduced quantum trajectory. 相似文献
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计算了四能级Tripod-型原子系统中探针光极化率随其频率失谐量的变化曲线.结果表明,当触发光作用于该系统的一个共振跃迁能级时,可使探针光的吸收和色散在其电磁感应透明(Electromagnetically Induced Transparency,EIT)窗口(由耦合光产生)处发生显著变化.随着触发光Rabi频率的增加,探针光在EIT窗口的吸收显著降低,色散显著增加.这种由触发光引起的探针光极化率的变化对应着三阶Kerr非线性光学效应,这一效应在偏振量子相位门中有着潜在的应用价值. 相似文献
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UnexpectedPopulationInversioninaΛ-typeMedium¥GONGShangqing;DUSide;XUZhizhan(ShanghaiInstituteofOpticsandFineMechanics,Chinese... 相似文献