Based on coupled-wave theory,a new approach of deriving diffraction efficiency equation on reflecting volume Bragg gratings Was proposed,On the basis of the deriVed equation,the detailed theoretical modeling for diffraction of plane and Gaussian beams on reflecting volume Bragg gratings were obtained,and the diffraction efficiencies including plane monochromatic,divergent monochromatic,and polychromatic beams were analyzed.Numerical results show that the angular selectivity could be varied from more than 100 mrad to less than 0.01 mrad.and spectral selectivity could also be varied from more than 100 am to less than 0.1 nm.When angular divergence or spectral width equals the angular or spectral selectivity,the grating Can provide maximal diffraction efficiency of more than 88%.When angular divergence or spectral width is far less than the angular or spectral selectivity,the decrease of diffraction efficiency is insignificant,which is less.than 1% of plane monochromatic wave.%基于耦合波理论,提出了一种推导反射体布拉格光栅衍射效率方程的新方法.在被推导的衍射效率方程基础上,获得了平面单色和高斯光束反射体布拉格光栅衍射的详细理论模型,分析了平面单色、发散单色和多色光束的衍射效率.结果表明:平面单色波的角和谱选择性随光栅厚度和空间频率而变化,角选择性的范围从低于0.01mrad到超过100mrad,谱选择性的范围从低于0.1nm到超过100nm;当光束的角发散或谱宽等于光栅的角选择或谱选择性时,光栅能提供超过88%的衍射效率;当光束的角发散或谱宽远小于光栅的角选择或谱选择性时,光栅衍射效率下降不明显,不到平面单色波的1%.
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