约束冷原子气体的高增益Raman散射光谱

High-gain Raman scattering spectrum of trapped atomic gas

本文研究了不同外部环境中原子气体在强激光抽运下的相干Raman散射光谱,通过对固定无反弹原子气体(不考虑外部自由度)和自由原子气体增益光谱的理论计算,得到了和Mollow实验结果基本一致的光谱曲线.通过与Mollow谱线结构的比较,揭示了在微阱约束情况下原子气体存在不同于以上两种环境的高增益光谱,该谱线直接反应了约束阱的性质,谱线呈等间距梳状结构,谱线尖锐分辨率高,和传统的冷原子气体散射增益光谱的实验结果相比较有更大量级的光增益现象.论文还分析了散射谱线增益的物理机理,清晰地给出了约束情况下原子增益谱线的非线性Raman共振条件.

In this paper,the Raman scattering spectra of cold atomic gas in different environments are closely calculated.Comparing the spectra from the atoms in free and trapped environments,the calculation result gives a right spectrum structure for the free atoms and reveals a distinct high-gain spectrum exhibiting a comb-like structure for the harmonic trapped atoms.The spectral peaks of the trapped spectrum are uniformly distributed and the distance between adjacent spectral peaks exactly equals the frequency of the trap. The nonlinear gain scheme and the gain conditions of the Raman scattering process are clearly given in this paper.