共查询到17条相似文献,搜索用时 93 毫秒
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三能级Λ-型原子系统被非相干辐射场泵浦,系统处于稳态时产生无反转激光,本文分析无反转激光及增益的起源。 相似文献
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Xin Yang Dong Yan Qianqian Bao Yan Zhang Cuili Cui 《Central European Journal of Physics》2014,12(12):813-821
Owing to interference induced by spontaneous emission, the density-matrix equations in a three-level Λ-type system have an additional coherence term, which plays a critical role in modulating the inversionless gain and electromagnetically induced transparency effect. In addition, it is shown that spontaneously generated coherence (SGC) has an effect on the entanglement between an atom and a photon of the coupling laser field by calculating the degree of entanglement (DEM) of the atomic system. In this paper, we investigate the influence of the SGC effect on atom-photon entanglement in a Λ-type system, which generally remains a high entangled state. When an incoherent pump source is introduced, we find that the SGC effect could exert considerable influence on the atom reduced entropy under certain conditions for both transient and steady states. More interestingly, such an incoherent pump field could actively affect the short-time dynamic behaviors of the transient quantum entangled state at a certain range of pump rate as a typical coherent case. 相似文献
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研究了V型三能级原子玻色-爱因斯坦凝聚体与双模压缩相干态光场相互作用系统中原子激光的两个正交分量的压缩性质,并与三型三能级原子玻色-爱因斯坦凝聚体和双摸压缩相干态相互作用系中原子激光的压缩作了比较.结果表明:压缩相干态光场的初始压缩因子和凝聚体中原子间的相互作用强度对原子激光的两个正交分量的压缩有明显的影响,随光场压缩因子增大原子激光的压缩深度增加,而随原子间相互作用变强,对原子激光的正交分量的压缩的影响变浅. 相似文献
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It is shown that in an open V-type atomic system without incoherent pumping, the spontaneously generated coherence (SGC) can not only lead to lasing with inversion but also lead to lasing without inversion (LWI)including at resonance of the driving and probe fields. This conclusion is much different from that obtained in the corresponding closed V-type system. 相似文献
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本文讨论了在双Λ型原子系统中制备相干叠加态的方法:一个Λ型系统通过控制激光而另一个Λ型系统采用部分受激拉曼绝热通道的方法.在理论上分析了产生任意相干叠加态的可能性并且讨论了透热系统在产生相干叠加态过程中的重要性.研究表明,没有透热过程是不可能制备出任意的叠加态.应用数值方法验证理论分析是正确,并且指出任意叠加态的产生只与控制脉冲的时间延迟有关. 相似文献
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Using the technique of stimulated Raman adiabatic passage, we propose schemes for creating arbitrary coherent superposition states of atoms in four-level systems: a Λ-type system with twofold final states and a four-level ladder system. With the use of a control field, arbitrary coherent superposition states are created without the condition of multiphoton resonance. Suitable manipulation of detunings and the control field can create either a single state or any superposition states desired. 相似文献
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Random laser action in ZnO 总被引:1,自引:0,他引:1
We report a direct evidence of random laser in optically pumped ZnO powder. Discrete lasing modes are observed above threshold.
The laser emission spectra depend on the angle of observation and are random. The lasing action is attributed to the coherent
feedback due to recurrent light scattering in the powder. The lasing threshold intensity depends on the excitation volume.
Received: 15 September 1999 / Revised version: 2 February 2000 / Published online: 5 July 2000 相似文献
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