对正负一级能量之比测量光栅参量方法的改进

Improvement on Measuring Grating Parameters with Diffraction Orders of m=±1 Efficiencies Ratio

提出利用同一波长的入射光在双面入射时两个能量之比的比值对光栅的参量进行测量,进一步提高准确度。首先从理论上比较正弦面形光栅在单一面入射及双面入射时各种衍射效率对光栅表面粗糙度的敏感程度;然后模拟测量出该正弦面型光栅在双面入射情况下的光栅参量;最后成功反演出体积相位全息光栅的三个参量,其测量结果为0.080μm,1.452μm,20.5μm准确度比单一入射面情况(0.080μm,1.451μm,20.1μm)时要高。同时该法继承了原来方法的无损伤、操作简便、可重复、易推广、成本低等优点。

A method to measure the grating parameters with the incident efficiencies ratio from both sides of the grating with the same wavelength is proposed. The proposed method has a higher precision than the original approach with the diffraction orders of m=±1 efficiencies ratio from one side of the grating. Firstly, by comparing the sensitivity of diffraction efficiency ratio to surface roughness under the condition of one side incidence and two-side incidence, it is found the former is more sensitive than the latter; secondly, the sine surface grating parameters are simulated for two-side incidence; finally, the volume phase holographic grating parameters are obtained experimentally more accurately. Meanwhile, the new method retains the advantage of the original method, such as no damage, simplicity and low cost.