不同能量抽运场作用下瞬态电磁感应透明特性研究  

Investigation of Transient Properties of Electromagnetically Induced Transparency with Different Pump Laser Energy

作　　者：杨希华[1] 

机构地区：[1]华东师范大学物理系

出　　处：《中国激光》2004年第7期811-814,共4页Chinese Journal of Lasers

摘　　要：通过求解含时密度矩阵方程研究了不同能量抽运场作用下Λ型三能级系统的瞬态电磁感应透明特性 ,分析了不同能量抽运场作用下弱探测场的吸收、各能级的布居及相干项 ρ2 3 随时间的演变关系。结果表明 ,当抽运场能量较高时 ,系统可实现瞬态无反转放大 ;随着抽运场能量的减小 ,电磁感应透明将减弱 ,瞬态无反转放大将消失。由于探测场的吸收取决于抽运场的拉比频率与相干项 ρ2 3 的乘积 ,在强抽运场作用下 ,非零瞬态振荡相干项 ρ2 3 导致探测场的瞬态吸收和无反转放大 ,抽运场能量的减小将引起总的相干效应减弱 ,从而导致探测场的负吸收消失以及正吸收增强。The transient properties of electromagnetically induced transparency (EIT) with different pump laser energies in a Λ-type three-level system are studied by solving the time-dependent matrix equation. The time evolution of the probe laser absorption, the population of the three levels and the coherent term ρ 23 are analyzed. It is shown that transient amplification without inversion can be realized with high pump laser energy and that transient EIT would reduce and transient amplification without inversion would disappear with the decrease of the pump laser energy. Since the probe absorption depends on the product of Rabi frequency of the pump laser and the coherent term ρ 23, the nonzero damping coherent term ρ 23 results in the transient absorption and amplification without inversion at high pump laser energy, and the decrease of the coherence with the decrease of the pump laser energy leads to the disappearance of the amplification and enhancement of absorption.

关 键 词：激光物理 瞬态电磁感应透明 瞬态无反转放大 量子相干 

分 类 号：O431[机械工程—光学工程]