【摘要】 以Kogelnik的体相位光栅耦合波理论为基础,通过测量光折变体光栅的衍射效率与布喇格偏移角的关系曲线,并根据该曲线的3 dB带宽和旁瓣峰值的相对大小及其角度偏移量,可计算出光折变体光栅的折射率调制度和有效厚度。对LiNbO3:Fe晶体的实验测量结果很好地验证了该方法的可行性,其测量精度与数字全息术和马赫 曾德干涉仪的方法相当,但测量过程却更加简单。更多还原

【Abstract】 Based on the Kogelink′s coupled wave theory and by measuring the relationship between the diffraction efficiency and Bragg angle deviation of volume grating,the refractive index modulation depth and effective thickness of the photorefractive volume grating can be calculated according to the 3 dB bandwidth,relative peak value of side lobe and its corresponding Bragg angle devication in the relationship curve.The experimental results with LiNbO₃:Fe crystal are well in agreement with the theoretic analysis.The measurement accuracy is no worse than that of available methods based on digital holography and Mach-Zehnder interferometer.At the same time,the measurement process is much more simple.更多还原