分析组合型余弦光栅的衍射场

Diffraction fields of combined cosine-gratings

为了研究组合型余弦光栅的衍射场,采用波前相因子判断法并考虑到光栅孔径的影响,得到了组合型余弦光栅的衍射场所含基元成分,导出像面上的衍射场振幅分布公式,并数值模拟了像面上衍射场振幅分布和光强分布,最后得出各焦斑的半角宽度。结果表明,该研究可为余弦光栅用于滤波和光学信息处理技术提供一个理论基础。

In order to analyze diffraction fields of combined cosine-gratings, considering the influence of the limited aperture of the gratings, the elements of the diffraction fields of the combined cosine-gratings were obtained and the corresponding integral expressions of the diffraction fields were derived based on the method of wavefront phase-factors. Then the formulae of the amplitude distribution of diffraction fields were deduced. Finally the amplitude and intensity distribution along the axis, the transverse line-width and axial line-width of that real focal-spot were obtained. This study may further provide a theoretical foundation for the application of combined cosine-gratings in filtering and optical signal processing.