共查询到18条相似文献,搜索用时 62 毫秒
1.
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
2.
3.
4.
5.
在Y型四能级原子系统中理论分析了外加相干控制场的强度变化对电磁感应透明和Kerr非线性效应的影响.结果发现:当外加的耦合场和抽运场的强度从相等变得不相等时,原子系统对探测场的吸收曲线从一个透明窗口逐渐变成了具有两个透明点的增益区间,透明点的位置、增益值的大小以及增益区间的宽度都与变化着的外场的拉比频率密切相关;当两个外场强度较弱并且相对强度减小时,Kerr非线性效应有所增强但同时伴随有吸收;而当两个外场的强度较强并且相对强度增大时,Kerr非线性的峰值也随之增大并且逐渐与透明点对应,即获得了无吸收巨Kerr非线性效应.研究还发现,抽运场的强度变化对Kerr非线性增强的影响作用较耦合场要大. 相似文献
6.
7.
8.
9.
10.
研究了旋波近似下Kerr介质中双模压缩真空场与N型四能级原子双光子跃迁相互作用系统中光场的压缩效应及光子的统计性质.数值计算结果表明,在无Kerr介质的情况下,光场的两个正交分量的均方涨落均呈现周期性的压缩,光子周期性地交替呈现聚束和反聚束效应,光场两模之间总是呈现正相关,而且这种相关是非经典相关;Kerr介质的存在不利于光场均方涨落的压缩,但对光子统计性质没有明显的影响
关键词:
Kerr介质
四能级原子
双模压缩真空场
光场的量子特性 相似文献
11.
A four-level N-type atomic medium is considered to study the effect of spontaneous generated coherence(SGC) and Kerr nonlinearity on light pulse propagation. A light pulse is propagating inside the medium where each atom follows four-level N-type atom-field configuration of rubidium(85Rb) atom. The atom-field interaction leads to electromagnetically induced transparency(EIT) process. The atom-field interaction is accompanied by normal dispersion and in the presence of SGC and Kerr nonlinearity the dispersion property of the proposed atomic medium is modified,which leads to enhancement of positive group index of the medium. The enhancement of positive group index then leads to slow group velocity inside the medium. A more slow group velocity is also investigated by incorporated the collective effect of SGC and Kerr nonlinearity. The control of group velocity inside a four-level N-type atomic medium via collective effect of SGC and Kerr nonlinearity is the major part of this work. 相似文献
12.
A four-level N-type atomic medium is considered to study the effect of spontaneous generated coherence (SGC) and Kerr nonlinearity on light pulse propagation. A light pulse is propagating inside the medium where each atom follows four-level N-type atom-field configuration of rubidium (85Rb) atom. The atom-field interaction leads to electromagnetically induced transparency (EIT) process. The atom-field interaction is accompanied by normal dispersion and in the presence of SGC and Kerr nonlinearity the dispersion property of the proposed atomic medium is modified, which leads to enhancement of positive group index of the medium. The enhancement of positive group index then leads to slow group velocity inside the medium. A more slow group velocity is also investigated by incorporated the collective effect of SGC and Kerr nonlinearity. The control of group velocity inside a four-level N-type atomic medium via collective effect of SGC and Kerr nonlinearity is the major part of this work. 相似文献
13.
Wen-juan Jiang Jian-ping Song Huai-bin Zheng Bao-yin Yin 《Optics Communications》2009,282(1):101-1839
A theoretical investigation is carried out into the effect of spontaneously generated coherence (SGC) on Kerr nonlinearity of a four-level N-type system. It’s found that the Kerr nonlinearity can be obviously enhanced with SGC present. We attribute the enhancement of Kerr nonlinearity mainly to the generation of extra coherences induced by the superposition of the two SGC channels, and when the superposition is controlled by the interference between two SGC channels properly, the maximal Kerr nonlinearity does not only enter the electromagnetically induced transparency window as the spontaneous generated coherences intensify, but also gets enhanced about 10 times with very large SGC coefficients than that with no SGC effect. 相似文献
14.
对V型三能级原子系统与双激光场相互作用时诱发的量子干涉效应进行了研究,通过在原子能级几率振幅随时间演化的耦合方程中引入一个上两能级交叉耦合干涉项,讨论和分析了在不同条件下交叉耦合干涉项的相消作用以及量子干涉效庆对原子基态几率和原子系统受激吸收特性的影响。 相似文献
15.
电子-声子相互作用对柱形量子线中光学克尔效应的影响 总被引:1,自引:2,他引:1
本文利用密度矩阵方法研究了柱形量子线中的光学克尔效应, 重点讨论了电子-声子相互作用对其的影响,并以GaAs量子线为例进行了数值计算。结果显示,随着量子线半径R0的减小,光学克尔效应会逐渐增强;考虑了电子-声子相互作用时的光学克尔效应比未考虑电子-声子相互作用时的大20%多;量子线半径R0越小,峰越尖锐,峰值越强;当量子线半径R0大〖WTBZ〗于40 nm时,峰会逐渐消失. 相似文献
16.
为了研究量子相干性在腔量子电动力学系统中的动力学和分布特性,基于两个各自捕获原子系综的光学腔建立了双光学腔系统,腔与腔之间由光纤耦合.利用相对熵度量的量子相干性,引入量子相干非平衡性的概念,分析了系统中相干动力学和光纤-腔耦合强度对相干性分布的影响.结果表明:在强耦合极限下,光纤-腔耦合强度的增加有利于保持两腔中的原子的整体相干性;光纤-腔耦合强度、原子-腔耦合强度以及原子数三个参数之间满足特定条件时,腔内的原子相干性可以传输至另一个腔.考虑腔、光纤及原子都存在耗散的情形,对比了不同耗散速率和非耗散情形下的相干性演化,发现耗散使得耦合双腔系统的相干性以及各个腔中的原子相干性发生衰减. 相似文献
17.
Nonlinear susceptibility of a quantum dot (QD) embedded in a two-sided cavity, is studied theoretically from a weak-coupling to a strong-coupling regime. In the relevance of a quantum logic gate, the corresponding nonlinear phase shifts (Kerr effect) are estimated for coherent wavepackets including one photon on average. In the weak-coupling regime, the phase shift enhances strongly as a function of a coupling constant between the cavity photon and QD, and eventually saturates in the strong-coupling regime. We also show transmission spectra to evaluate the efficiency of the phase shift. Although the efficiency decreases monotonically in the weak-coupling regime, it rises in the strong-coupling regime. 相似文献