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利用适当的坐标变换和黎曼方法建立了高斯光束在单轴晶体中布拉格衍射的严格的耦合波理论 ,获得了一组严格的耦合波方程和衍射效率计算公式 ,讨论了衍射效率随折射率调制量的关系以及波长选择性和角度选择性 ,同时分析了衍射效率对再现光宽度的要求。模拟计算表明 ,异常光与异常光 (ee)型布拉格衍射能够达到的最大衍射效率由记录时入射角决定 ,而且通过各参量的适当的选择 ,理论上ee型布拉格衍射能够在折射率调制量很低(如 8.2× 10 -5)的情况下获得接近 90 %的衍射效率。该理论模型为如何在较低折射率调制量下获得较高衍射效率提供了理论指导
A rigorous coupling wave theory of Bragg diffraction of Gaussian beam in uniaxial crystal was established by means of appropriate coordinate transformation and Riemann method. A series of strict formulas of coupled wave equation and diffraction efficiency were obtained. The diffraction efficiency was discussed with the refractive index modulation Quantity relationship and wavelength selectivity and angle selectivity, at the same time analyzed the diffraction efficiency of the reproduction light width requirements. The simulation results show that the maximum diffraction efficiency that can be achieved by the Aberration and Abnormal Bragg diffraction is determined by the incident angle of recording. With the proper choice of each parameter, ee type Bragg diffraction can theoretically be used in the case of high refractive index modulation Nearly 90% diffraction efficiency is achieved with low (eg 8.2 × 10 -5). The theoretical model provides theoretical guidance on how to obtain higher diffraction efficiency at lower refractive index modulations