He Guang, Lin Tzu-Chau, Prasad Paras
Opt Express. 2004 Nov 29;12(24):5952-61. doi: 10.1364/opex.12.005952.
A frequency-unshifted and backward stimulated Rayleigh scattering can be produced in a linearly transparent but two-photon absorbing medium. Using a novel two-photon active dye solution as the nonlinear medium pumped by 532-nm and ~10-ns laser pulses, a highly directional backward stimulated scattering at the pump wavelength can be readily observed. The experimental results on spectral structure, spatial and temporal behaviors, and output/input relationship of this new type of stimulated scattering are presented. To explain the observed phenomenon and its experimental behaviors, a physical model of feedback mechanism provided by a two-photon-excitation enhanced Bragg grating inside the scattering medium is proposed. Comparing to other types of stimulated scattering, the stimulated Rayleigh-Bragg scattering exhibits the advantages of no-frequency shift, low threshold, and low requirement for pump spectral line-width.
在一种线性透明但具有双光子吸收特性的介质中，可以产生频率未发生偏移的背向受激瑞利散射。使用一种新型双光子活性染料溶液作为非线性介质，并由532纳米、脉宽约10纳秒的激光脉冲泵浦，能够很容易地观测到在泵浦波长处产生的高定向背向受激散射。本文给出了这种新型受激散射的光谱结构、空间和时间特性以及输出/输入关系的实验结果。为了解释所观测到的现象及其实验特性，提出了一种由散射介质内部双光子激发增强布拉格光栅提供反馈机制的物理模型。与其他类型的受激散射相比，受激瑞利-布拉格散射具有无频率偏移、阈值低以及对泵浦光谱线宽要求低等优点。
