菌紫质同线偏振全息记录时再现光偏振方向对衍射效率的调制

当用相同偏振方向的物光和参考光在菌紫质薄膜上记录光栅时，再现光的偏振方向会影响其衍射效率.采用琼斯矩阵方法对此进行了理论分析，结果显示，再现光的偏振方向对衍射光的光强产生余弦调制；当再现光的偏振方向平行或垂直于记录光的偏振方向时，衍射光仍为线偏振光，其他情况下衍射光均变成椭圆偏振光.再现光偏振方向对衍射效率峰值的调制为正向余弦调制，对衍射效率稳定值的调制为反向余弦调制(与前者在相位上相差π).加入辅助紫光可抑制光栅的饱和，从而使得再现光偏振对衍射效率稳定值的调制由反向余弦调制变为正向余弦调制，并且提高了衍关键词：菌紫质光致各向异性衍射效率琼斯矩阵

Modulation of the azimuth of polarization of reconstruction beam on the diffraction efficiency of anisotropic gratings recorded in bacteriorhodopsin films by two parallel linearly polarized beams

When the linearly polarized object and reference beams with the same polarization direction are used for recording gratings in bacteriorhodopsin films, the azimuth of polarization of the reconstruction beam has an influence on the diffraction efficiency. By using Jones matrices to analyze this phenomenon, we find that the azimuth of polarization of the reconstruction beam makes a cosine modulation on the diffraction efficiency. The diffracted beam is linearly polarized only when the polarization of the reconstruction beam is parallel or perpendicular to that of the recording beams; otherwise, the diffracted beam becomes elliptically polarized. The azimuth of polarization of the reconstruction beam produces a positive cosine modulation on the peak diffraction efficiency, but a negative cosine modulation on the steady diffraction efficiency (with phase difference π). By adding auxiliary violet light during grating formation, the saturation of the grating can be restrained; as a result, the negative cosine modulation of the steady diffraction efficiency changes to the positive cosine modulation and also the steady diffraction efficiency is increased apparently.