共查询到18条相似文献,搜索用时 109 毫秒
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文章讨论了在驱动场作用下,三能级原子在光子晶体中的自发辐射问题。由于量子干涉和光的局域化作用,两个上能级中的布居数将具有周期振荡或准周期振荡的性质, 相似文献
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研究了动态各向同性光子晶体中二能级原子自发辐射的性质,主要讨论了光子晶体能带带边频率随时间作阶跃调制和三角函数周期调制两种情况下,原子上能级占据数随时间的演化特性.当光子晶体能带带边频率随时间作阶跃调制时,原子上能级占据数随时间的演化不仅和上能级与能带带边的相对位置δ有关,更依赖于阶跃调制发生的时刻.调制发生时刻不同,调制后原子上能级占据数随时间的演化也不同.当光子晶体能带带边频率随时间作三角函数周期调制时,二能级原子上能级占据数随时间作总体衰减的准周期振荡.通过选择调制频率和调制初相位可调控准周期振荡的频率、峰值与谷值的大小以及占据数的总体衰减速度等. 相似文献
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光子晶体中二能级原子的自发辐射 总被引:3,自引:0,他引:3
研究光子晶体中二能级原子的自发辐射。由于光的局域化以及缀饰态之间的量子相互作用 ,由局域场、传输场、弥散场组成的原子的辐射场发生变化 :随着激发态能级由禁带移往通带 ,发现局域场中的能量通过弥散场向传输场转移。当局域场和传输场共存时 ,激发态能级上的原子布居数的演化具有准振荡行为 ;当局域场和传输场不共存时 ,原子布居数的演化不具有准振荡行为。另外 ,激发态能级上的稳态原子布居数也发生改变。这些性质不仅依赖于原子的激发态能级ω1与光子频率能带边缘ωc 的相对位置δ,同时也依赖于光子晶体中带边缘的光子态密度 ρ(ωk) (或带边光滑参数ε)。 相似文献
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《物理学报》2017,(1)
研究了动态各向同性光子晶体中V型三能级原子的自发辐射,主要讨论了光子晶体能带带边频率受到阶跃调制和三角函数周期调制两种情况下,调制参数对占据数演化的控制作用,以及此过程中量子相干效应带来的影响.结果表明,阶跃调制时,调制发生后原子上能级劈裂出来的束缚缀饰态数目只取决于原子的跃迁频率和此时的带边频率,且与具有相同参数条件的静态情形下的相同.调制发生时刻对其后原子上能级占据数的长时演化情况有影响.随系统初态的不同,量子相干效应既可导致调制之后占据数迅速衰减,也可使原子上能级保留较多的占据数.三角函数周期调制时,原子上能级总占据数在足够长的时间之后随时间做频率近似等于调制频率的有衰减的准周期振荡.衰减率与调制频率有关,也因量子相干效应而受系统初态以及偶极矩夹角的影响. 相似文献
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The two models of three-level (one upper level and two lower levels, or two upper levels and one lower level) atom embedded in a double-band photonic crystal are adopted. The atomic transitions from the upper levels to the lower levels are assumed to be coupled by the same reservoir which are respectively the isotropic photonic band gap (PBG) modes, the anisotropic PBG modes and the free vacuum modes. The effects of the fine structure of the atomic ground state levels in the model with one upper level and two lower levels, and the quantum interferences in the model with two upper levels and one lower level on the spontaneous emission spectrum of an atom are investigated in detail. Most interestingly, it is shown that new spontaneous emission lines are produced from the fine splitting of atomic ground state levels in the isotropic PBG case. The quantum interferences induce additional narrow spontaneous lines near the transition from the empty upper level to the lower level. 相似文献
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Ronggang Liu 《International Journal of Theoretical Physics》2014,53(12):4351-4359
We investigate the spontaneous emission spectrum of a five-level M-type atom driven by a microwave field, in which one lower level is coupled by the same modified reservoir to two upper levels. The results show that a few interesting phenomena in spontaneous emission spectra, such as spectral-line shift, spectral-line enhancement and spectral-line suppression, which can be controlled by adjusting the proper parameters of the system. These phenomena can originate from quantum interference of the strong coupling system. 相似文献
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We study the coherent control of spontaneous emission of a double-driven four-level atom embedded in photonic crystals. Combined effect of different relative locations between the upper band edge and the two upper levels and the phase of microwave coupling field is discussed. It is shown that quantum interference effect such as laser-induced dark line depends strongly on the phase of microwave field. 相似文献
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S. Y. Xie Y. P. Yang 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2007,42(1):163-177
We investigate the spontaneous radiation from a ladder three-level atom
embedded in a three-dimensional anisotropic photonic crystal with an
external driving field. The properties of the spontaneous emission are
dependent strongly on the relative position of the middle level from the
band edge. Due to the Autler-Townes splitting by the action of the driving
field, the external driving field can also affect the properties of the
spontaneous emission. The population exchanged between the upper and the
middle levels decreases as the detuning of the external driving field
frequency from the corresponding transition frequency increases. The
properties of the emission field can be changed or so much as controlled by
choosing suitable intensity of the external driving field. The emission
spectrum is more complex, and dependent on the location of the observer in
this case. 相似文献