一种测量材料热光系数的实验方法

摘要

This paper presents a simple method to determine the thermal coefficient (the refractive index of optical material with temperature change rate) of the material.When Gauss continuous laser irradiation on a specimen of the material,the material will absorb part of the energy of laser,thermal lens effect will be produced,it can make the laser phase change.The size of the far field spot will change when the laser passes through the material produced by the thermal lens effect.Using common CCD to collect spot images,and analyzing the change of far-field spot size,one can get the thermal lens effect size produced on the material,so as to obtain the thermal optic coefficient of the material.Compared with the traditional measurement method,this method has the advantages of convenient operation,optical system is simple and the principle is easy to understand.It can be used as a demonstration experiment of college physics of modern optics.%提出一种简单测量材料热光系数(光学材料折射率随温度的变化率)的方法.当高斯连续激光作用在材料样品上时,材料会吸收激光中部分能量,产生热透镜效应,使材料中激光的相位发生变化.当激光通过产生热透镜效应的材料后,远场光斑的大小就会发生改变.使用普通CCD采集远场光斑的图像,通过对远场光斑大小变化进行测量分析,得到材料在激光作用下产生热透镜效应的大小,从而获取材料样品的热光系数.与传统的测量方法比较,该实验方法操作方便,实验中光路系统及原理简单易懂,可作为大学物理现代光学的演示实验.