在Kogelnik耦合波理论的基础上,考虑光栅记录介质的色散效应的影响,研究了光折变体全息光栅对不同偏振状态的超短脉冲激光光束衍射的性质,讨论了高斯型入射脉冲激光光束的谱宽与光栅的有效衍射谱宽之比不同时,衍射和透射光束的光谱宽度、时间宽度、波形和衍射效率的变化。结果表明,光栅的有效衍射谱宽受光栅参量及入射条件的影响,对衍射性质的影响很大,且在考虑光栅记录介质的色散效应时减小。当入射脉冲的偏振方向垂直于入射面时,光栅的有效衍射谱宽大于偏振方向平行于入射面的情形,衍射效率在入射脉冲宽度较大时小于偏振方向平行于入射面的情形;谱宽比较大时,衍射光束的时间分布曲线产生展宽和变形,且比偏振方向平行于入射面的情形展宽和变形得更加明显。

Considering the dispersion effect of the grating media, the coupled wave theory of Kogelnik was developed to study the diffraction properties of an ultra-short pulsed laser beam with different polarization states by a photorefractive volume holographic grating. The spectral and temporal width, the distortion of the diffraction and transmission pulse beam, as well as the diffraction efficiency were studied, as a transmission volume holographic grating was illuminated by an ultrashort Gaussian-shaped pulsed laser beam and the ratio of the input laser beam spectral width and the effective diffraction spectral width of the grating varied. It was investigated that the effective diffraction spectral width of the volume grating was affected by the parameters of the grating and the input conditions, and decreased by the dispersion effect of the grating media. The effective diffraction spectral width of the incident pulse with polarization perpendicular to the incident plane was larger than that of the pulse with parallel polarization state, and with a relatively long pulse duration the diffraction efficiency of the former was larger than that of the latter. With a relatively large spectral width ratio, there appeared expansion and distortion for the temporal distribution curve of the diffraction beam, which were more obvious for the beam with polarization perpendicular to the incident angle.