激光散斑均化对防护测量的影响

目的：介绍基于散斑原理实现均化激光光宽的方法并研究其对防护镜防护性能评定带来的影响。方法：实验中用Nd：YAG脉冲激光器作为激光源．发射波长为532nm、频率为1Hz、光束直径为5ram的激光。分别将低阶模或高阶模激光源发散后，光路中置入毛玻璃相位板或散斑相移器，测量防护镜片的光密度值，并与常规测量方法进行比对，以观察激光散瘫均化后对防护测量的影响。结果：在测量中，只要加入均化装置。监视比和透射比的标准偏差都将减小（不同组间方差分析P〈0．01）．有时甚至能提高一个量级；在光束发散条件下测量防护镜的光密度值与常规测试结果有一定规律性差异；加均化与无均化2种条件下所测光密度值略有差异，相对偏差〈5％。结论：激光散斑均化能提高防护镜片测量稳定度：激光源的模式、光源的发散态和均化程度对镜片光密度测量值都有影响。

Effect of Laser Speckle-homogeneity on Protective Measurement

Objective To introduce a method to average the laser energy based on speckle interferometry and evaluate its effect on the optical density-measurement of laser goggles. Methods A pulsed Nd：YAG laser of wavelength 532nm, repeated frequency of 1 Hz and 5mm of laser beam diameter was used in the experiment. A ground glass-phase plate or spackle- phase shifter was used in the low-order mode or high-order mode laser optical path, to measure goggles-optical density in the same optical path and studied effect of laser speckle-homogeneity on protective- measurement. Results Standard deviation of transmittance was cut down if the homogeneity-equipment was added in the optical path（P〈0.01 ）. Sometimes it could enhance one order of magnitude. Measured value of goggles-optical density was changed regularly when laser beam was dispersed. The measured value had a little discrepancy if the homogeneity-equipment was used （most of relative deviation was less than 5%）. Conclusions The degree of stability of measurement is improved by laser speckle-homogeneity. The measure of goggles-optical density can be changed by laser-mode, beam-situation and spot energy-average.Chinese Medical Equipment dournal,2010,31 （2） ：21-23,42]