阶梯形浮雕和折射率位相光栅的衍射性质比较

位相全息图一般既有浮雕调制又有折射率调制，它们都会对衍射特性产生影响。利用以严格电磁波理论为基础的模式匹配法（ＭＭＴ），从理论上比较了阶梯形浮雕位相调制光栅和折射率位相调制光栅对ＴＥ波的各级衍射效率。尽管它们同一周期内的相应部分所引起的位相变化相同，但随着光栅层厚度的加大两种位相调制光栅的各级衍射效率会出现差别。这种差别与周期有关。并将矢量理论的结果与标量理论的结果进行了比较，研究结果对研究全息术

A Comparison of the Diffraction Property between Step Type Relief and Refractory Index Phase Gratings

A phase hologram not only has relief modulation but also has refractory index modulation,both modulation will affect the diffraction property of the phase hologram.By means of a mode matching method based on strict electromagnetic wave theory,the diffraction efficiency of the step type relief phase modulation grating and refractory index phase modulation grating for TE wave at various levels are compared in theory.In spite of that the phase variation caused by the corresponding part in the same period is identical.with the enlargement of thickness in grating layer,a difference will be appeared in the diffraction efficiency at various levels of two kind of phase modulation gratings.This difference is concerned with the period.A comparison between the result of vector theory and the result of scalar theory is carried out.The research results have an important significance for studying holography and evaluating of hologram quality.