讨论了在铯(Cs)原子蒸气中的光学三阶谐波的产生。理论分析表明，铯的非线性极化率系数Ｘ(3)(3ω)在λ＝1.0790 μｍ处存在双光子共振增强效应，给出了为达到位相匹配所需的温度。实验获得了1.0790 μｍ光波作用于Cs所产生的三阶谐波谱线(359.7 μｍ)的照片。

Optical third-harmonic generation in Cesium medal vapor is discussed in this paper.The theoretical analysis shows that there is a two-photon resonance enhancement effect for nonlinear susceptibility Ｘ(3)(3ω)of Cesium at wavelength 1.0790 μm.The temperature which is necessary to achieve phase matching is given. It's the first time that the third-harmonic spectral line(359.7 μｍ) of the fundamental wave 1.0790 μm in Cesium vapor is photographed experimentally.