偏振激光散斑的相关性研究

采用发送一束线偏振激光产生散斑的方法，研究线偏振激光散斑、＂平均椭圆偏振＂激光散斑以及非偏振激光散斑的相关性和精细结构。指出：当漫射器为一片毛玻璃时，散斑激光是线偏振的．其方向与入射激光束相同；当漫射器为涂无光白漆的毛玻璃时，散斑激光是部分或全部退偏的，涂层越厚，退偏越甚。对于强线偏振散斑场，当偏振方向改变时，散斑的精细结构无明显变化，即使是两个正交方向上的散斑图，也保持良好的相关性。对于非偏振散斑场，当照明激光束的偏振方向改变时．散斑精细结构有明显变化。

EXPERIMENTAL STUDY ON THE CORRELATION OF POLARIZED LASER SPECKLES

An experimental study of the state of polarization of laser speckles generated by sending a linear polarized laser beam through a diffuser is presented in this paper. We pay close attention to the study of the correlation and microstructure of the linear-polarization laser speckles and the non-polarized laser speckles. It is found that in the case of a ground glass the resulting speckles are linearly polarized as that of the illuminating beam. Howerer, the state of linear polariztion degenerates into partial depolarization, or full depolarization, i. e. an average elliptical polarization when the scattering surface of the ground glass is altered by a thin layer of white paint, and the degeneration increases as the coating thickens. For a strongly linearpolarized speckle field the microstructure of speckles does not vary appreciably as the direction of polarization is changed. As a result, strong correlation is maintained even for two orthogonally polarized speckle patterns. On the other hand, for a "depolarized" speckle field, the speckle microstructure changes significantly as the polarization direction of the illuminating beam is altered.