用光栅的正负一级能量之比测体积相位全息光栅参量

Determining the Parameters of VPHG with the Diffractive Efficiencies Ratio(+1/-1)

提出利用光栅衍射级次正负一级的能量之比(w+1/w-1),结合模拟退火优化算法来反演出光栅参量的一种方法.用正负一级的能量之比来弱化实际光栅表面存在的粗糙、周期畸变、介质折射率分布不均匀等误差,保证光栅参量的准确反演.在反演体积相位全息光栅参量的实验中,反演出的光栅参量与真值的误差不超过1%.证明了该法的正确性和可行性.同时此方法具有非破坏性,测量简单,操作方便,稳定性好等特点.

A new method is proposed to determinate the parameters of the gratings at the same time by means of the diffractive efficiencies ratio （＋1/-1） and simulated annealing algorithm. We make use of the diffraction orders efficiency ratio （m= ＋ 1 ,-1） decrease the error result from the varied degree surface roughness, the aberration in the structure period and the medium distributing uneven etc, in order to ensure to calculation precision in the optimized method. In the experiment of determining the Volume Phase Holographic Grating＇s parameters, the error of the result is not over 1%, so it demonstrates the metrology＇s validity and feasibility. At the same time, It has a lot of advantages such as no damage, simplicity of measurement, facility of manipulation, good stability and so on.. we believe that the metrology will become the powerful instrument in measurement the grating constant.