研究了具有高斯横向分布的连续激光束单次通过铷原子蒸气后,在近共振附近铷原子蒸气中,由强的非线性克尔效应导致激光分裂成细丝的现象,并且这些细丝的衍射图样在远场通过相干叠加,可以形成具有规则结构的斑图模式.实验上研究了输入光功率,铷泡温度和抽运激光频率相对于85Rb原子D2线的不同失谐位置等因素对斑图模式的影响.由于铷原子的超精细能级结构,在铷原子蒸气中同时存在与三阶非线性效应相关的四波混频现象,通过扫描探测光的频率同时观察到具有斯托克斯和反斯托克斯光子的拉曼增益现象.
There are abundant nonlinear effects in atomic vapor. In this paper, the phenomenon of laser breaking up into filaments is studied in the near-resonant rubidium atomic vapor, which is induced by the strong nonlinear Kerr effect. When the continuous - wave laser beam with transverse Gaussian distribution passes through the atomic vapor, the pattern arising from the coherent superposition of the diffraction patterns of filaments is observed. We also investigated the influence on the mode pattern by input power of laser, the temperature of the vapor cell and the frequency detuning of pump light. Due to the hyperfine structure of rubidium atoms, the four-wave mixing effect exists in hot rubidium atomic vapor, which is related to the third-order nonlinear effect closely. The Raman gain of the Stokes and anti - Stokes photons is observed by scanning the frequency of the probe beam.