中国激光, 2004, 31 (7): 811, 网络出版: 2006-06-12
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
激光物理 瞬态电磁感应透明 瞬态无反转放大 量子相干 laser physics transient electromagnetically induced transparenc transient amplification without inversion quantum coherence
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ρ23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ρ23的乘积,在强抽运场作用下,非零瞬态振荡相干项ρ23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。
Abstract
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 ρ23 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 ρ23, the nonzero damping coherent term ρ23 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.
杨希华. 不同能量抽运场作用下瞬态电磁感应透明特性研究[J]. 中国激光, 2004, 31(7): 811. 杨希华. Investigation of Transient Properties of Electromagnetically Induced Transparency with Different Pump Laser Energy[J]. Chinese Journal of Lasers, 2004, 31(7): 811.