SrWO_4晶体受激拉曼散射的各向异性

Anisotropy of stimulated Raman scattering in SrWO_4 crystal

以四方晶系SrWO4晶体为例,研究其非主轴偏振配置的受激拉曼散射特性。用532nm皮秒脉冲激光作为泵浦源,以单次通过的方式研究了a切SrWO4晶体的受激拉曼散射增益随泵浦光偏振方向的变化,由此确定出拉曼增益的各向异性。针对由[WO4]2-四面体对称伸缩引起的924cm-1的最强频移的实验显示:当入射光沿a轴和c轴偏振时,拉曼增益系数出现两个极大值,增益分别为10.1cm/GW和14.2cm/GW;当入射光沿a,c轴中分线方向偏振时,拉曼增益系数出现两个极小值,为7.1cm/GW。结合拉曼张量及非极性晶格振动模拉曼散射强度解释了上述物理现象,证明了实验结果与理论相符。

The relationship between stimulated Raman scattering characteristics and the polarization direction of a pump light was researched by taking an a-cut SrWO4 crystal which belongs to the tetragonal crystal system as a research object. Using a 532 nm light as the pump source and a single passing way as implementation, the anisotropy for the SRS＇ gain of a-cut SrWO4 crystal was determined. The experimental results on the strongest Raman frequency shifting of 924 cm 1 come from the sym- metrical stretching vibration of [WO4 ]2 tetrahedron show that the gain coefficients appear two maxi- mum values of 10.1 cm/GW and 14.2 cm/GW respectively when the pump light is polarized on a and c axes, and the gain coefficients present two of the same minimal values of 7. 1 cm/GW when the pump light is polarized along the bisector of a and c axes. The results are interpreted using a Raman tensor and the nonpolar Raman scattering intensity theory, which demonstrates that experimental results in this paper are in good agreement with that of the theory.