三能级系统电子分布转移的数值模拟

Numerical simulation of population transfer of three-level system

原子能级中的分布可以人为的加以控制 ,受激拉曼迁移过程为我们提供了一种有效转移电子分布的方法 ,特别是可以有选择地实现分子高振动能级的分布转移。要对该过程有一个全面的了解 ,就必须对偏离共振和激光强度对电子分布转移所产生的影响有深刻的认识。使用数值模拟的方法系统地分析了三能级系统在受激拉曼迁移过程中电子分布的转移情况 ,计算了系统处于双光子共振时和偏离共振时的转移率 ,分析了偏离双光子共振、偏离单光子共振以及两束激光相对强度对转移率的影响。计算结果表明在双光子共振时可以完全转移 ;当偏离双光子共振很小的时候 ,基本可以达到完全转移 ;转移率对两束激光的相对强度不是很敏感。

It is possible to prepare atoms or molecules in a selected excited state, one efficient way is to transfer population by stimulated-Raman-adiabatic-passage, but must understand off-resonant effects in coherent excitation in order to improve the efficient of transfer. Here, consider the transfer of population in a three-level system of stimulated-Raman- adiabatic-passage with computer analysis. The transfer efficiency of two-photon resonant is worked out and the outcome demonstrates the possibility of complete transfer. Also analysis the effect of two-photon off-resonant, single-photon off-resonant and difference of laser's intension.