共查询到17条相似文献,搜索用时 93 毫秒
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量子微腔中腔场衰变对运动原子自发辐射的影响 总被引:1,自引:0,他引:1
通过分析环形微腔中单模量子电磁场与低速运动二能级原子相互作用过程中光子与原子质心的动量交换效应,本文详细研究了原子质心的运动多谱勒效应及光子反冲对原子能级自发辐射寿命的影响,本文理论证明了这效应起因子腔壁引起腔模的衰变,在一定条件下,原子质心运动将增强或低原子的自发辐射。 相似文献
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双模腔场中两原子自发辐射线型的一般理论 总被引:4,自引:0,他引:4
本文研究了两个双能级原子与双模真空腔场具有不同耦合常数(g1≠g2)时的自发辐射线型.一般情况下,两原子系统的"双模真空场拉比劈裂"存在对称十峰结构;在R=g2/g1从0.25增加到0.75的过程中,自发辐射线型交替出现对称八峰和十峰结构;双模真空场中单原子的对称双峰结构以及两等同原子的对称六峰结构可作为特例得出.另一方面,本文给出了上述谱特性的物理解释. 相似文献
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唐文涛 《原子与分子物理学报》2013,30(6)
利用格林函数和费米黄金定律,我们计算了单镜面附近的激发态极化原子的自发辐射率。结果表明:原子的自发辐射与原子的极化偶极距取向有关,并且随着原子与镜面间距的增大,辐射率呈现正弦形式的振荡。当偶极距取向与镜面方向平行时,自发辐射的正弦式振荡最为激烈。但是随着极化方向与镜面方向夹角的增大,自发辐射的振荡越来越弱。当偶极距取向与镜面垂直时,振荡几乎消失。利用光子的闭合轨道理论,我们可以发现激发态原子偶极距取向影响辐射光子数的多少,从而可以改变原子的自发辐射率。 相似文献
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利用腔量子电动力学计算了原子在全反射镜面附近的自发辐射率。结果表明,所得的震荡谱和原子到镜面的距离有关。通过傅立叶变换,得到与这些振荡谱相对应的频率谱。为了解释这种现象,我们首次将闭合轨道理论用于研究辐射原子在单镜面附近的自发辐射率,给出了对原子自发辐射现象新的理论解释。 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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近年来,左手材料的研究引起了人们极大的兴趣。左手材料通常由亚波长金属微结构(尺度远小于波长)构成,存在着电等离子体振荡频率和磁等离子体振荡频率。人们已经开始关注左手材料中原子的辐射性质,但以往的研究主要针对原子跃迁频率远离介质(等离子体)共振频率的情况。我们针对二能级原子跃迁频率和介质等离子体振荡频率共振的情况作了理论研究。由于在介质共振频率附近真空场被强烈改变了,计算结果表明其中的原子的自发辐射性质与自由空间中有明显不同。应用自发辐射的非马尔可夫理论,我们发现原子和介质中真空场的相互作用导致了原子-光场束缚态的出现。我们进一步分析了介质吸收对自发辐射的影响,证明存在吸收时在一定条件下原子和真空场的相互作用的特性仍可以得以保持。 相似文献
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利用光子的闭合轨道理论,我们研究了原子在两个平行镜面间两层电介质板(折射率分别为n1,n2)中的自发辐射率. 自发辐射率呈现出多周期的振荡结构。自发辐射率的傅立叶变换中的每一个峰和光子从原子出发到返回原子的一条闭合轨道相对应。结果表明自发辐射率和两层电介质的宽度和折射率有关。和只有一层电介质的辐射率比较,当两层电介质的折射率n1 和 n2 差别很小时, 两层电介质之间分界面的反射效应可以忽略;但是当二者的差别很大时,发射效应变得非常重要且自发辐射率中的振荡减弱。本文的结果为原子在不同电介质间的自发辐射率的研究提供了新的理解。 相似文献
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We study three-body entanglement induced by spontaneous
emission in a three two-level atoms system by using the entanglement
tensor approach. The results show that the amount of entanglement
is strongly dependent on the initial state of the system and the species
of atoms. The three-body entanglement is the result of the coherent
superposition of the two-body entanglements. The larger the
two-body entanglement is, the stronger the three-body entanglement
is. On the other hand, if there exists a great difference in three two-body entanglement measures,
the three-body entanglement is very weak.
We also find that the maximum of the two-body entanglement
obtained with nonidentical atoms is greater than that obtained
with identical atoms via adjusting the difference in atomic frequency. 相似文献
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Spontaneous emission behavior from atoms (or molecules) in one-dimensional photonic crystal with a defect is investigated. Taken all the TE and TM modes into account, the normalized spontaneous emission rate of the atom is calculated as a function of the position of the atom in the crystal. Results for both nonabsorbing dielectric structure and absorbing dielectric structure are presented. With the increase of the thickness of the defect in which the atoms are embedded, the oscillations of the spontaneous emission rate versus the position of the atom become dense and the lifetime distribution becomes narrow and sharp. The PC effect may lead to the coexistence of both accelerated and inhibited decay processes. 相似文献
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唐文涛 《原子与分子物理学报》2014,31(1):94-99
利用格林函数和费米黄金定律,我们计算了单镜面附近的激发态极化原子的自发辐射率.结果表明:原子的自发辐射与原子的极化偶极距取向有关,并且随着原子与镜面间距的增大,辐射率呈现正弦形式的振荡.当偶极距取向与镜面方向平行时,自发辐射的正弦式振荡最为激烈.但是随着极化方向与镜面方向夹角的增大,自发辐射的振荡越来越弱.当偶极距取向与镜面垂直时,振荡几乎消失.利用光子的闭合轨道理论,我们可以发现激发态原子偶极距取向影响辐射光子数的多少,从而可以改变原子的自发辐射率. 相似文献
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The microcavity and the influence of nonradiative recombination can control spontaneous emission. An analytic resolution of rate equation is studied for microcavity lasers. The relationship between output prop- erties and structural parameters of multi-quantum wells (MQWs) is obtained. One of the most important consequences of the incrcased spontaneous emission factor is the reduction of laser threshold. It is found that the characteristic curve of a "thresholdless" laser is strongly nonradiative depopulation-dependent. The light output is increased by the enhanced well number and the reduced width. In particular, there is an optimal well number corresponding to the lowest threshold current density for MQW structure in the microcavity lasers. 相似文献
15.
Jiunn-Woei Liaw Chi-San Chen 《Journal of Quantitative Spectroscopy & Radiative Transfer》2010,111(3):454-465
The plasmonic effects of a metallic (Au or Ag) nanodimer on the excitation and emission of a single emitter placed within the gap of the nanodimer are studied to identify its overall performance (enhancement or quenching) for the spontaneous emission. The process of a spontaneous emission is divided into two stages for analysis: the excitation and the subsequent emission stages. For the excitation stage, the amplification of the local electric field around the gap region is studied to show the converging-lens effect of the nanodimer for focusing an incident light. For the emission stage, the apparent quantum yield of an electric dipole (the excited emitter) in the presence of the nanodimer is studied in terms of its radiative and nonradiative decay rates. Both models are simulated by the multiple multi-pole methods for solving Maxwell's equations. The results indicate that the overall enhancement factor of a metallic nanodimer on the spontaneous emission depends not only on its dimension (radius and gap) but also on the absorption and emission spectra of the emitter. Moreover, there is an optimal dimension (radius and gap) of a nanodimer for obtaining the maximum enhancement to a specific spontaneous emission. In addition, the observed emission spectrum of the emitter can be modified by the nearby nanodimer (a low-pass filter), and its lifetime can be reduced by two or three orders of magnitude due to the energy transfer between them. 相似文献
16.
Through picture of dressed states, this paper investigates
the spontaneous emission spectrum from a microwave-driven
three-level atom embedded in a double-band photonic crystals. The
physical dynamics of the phase dependent phenomenon is analysed by
comparing two models `upper level coupling' and `lower level
coupling'. When the phase is changed from 0 to $\pi$, the variety of
spontaneous emission spectra from either of the two models are
inverse to each other, in which the relative height and width of
peaks are determined by the density of states in photonic crystals. 相似文献
17.
The suppression of amplified spontaneous emission (ASE) that arises during the femtosecond chirped-pulse amplification is presented. On the basis of the distinct differences in the spatial, temporal and spectral region between ASE and the amplified laser signal, the noise arising from ASE was effectively filtered out. The ratio between the amplified femtosecond pulse and the ASE peak power was higher than 107. Pulses as short as 38 fs were amplified to peak power of 1.4 TW. 相似文献