一、引言最近几年,随着激光研究与激光应用的发展,在物理教学和科学研究过程中开始愈来愈多地使用新型光源——激光器。尤其是功率不大的小型氦氖激光器,价格便宜使用方便,这类激光器已经成了实验室里必不可少的工具。安全使用激光器问题,早已引起人们的注意。由于眼球本身具有聚焦作用,激光器所发射的激光束特别容易损伤人的眼睛,在这方面我们也是有教训的。一名技术人员调 I. INTRODUCTION In recent years, with the development of laser research and laser application, more and more new type of light sources - lasers have been used in physics teaching and scientific research. Especially the small power HeNe laser, cheap and easy to use, such lasers have become an indispensable tool in the laboratory. The safe use of lasers has long drawn people’s attention. As the eye itself has a focusing effect, the laser beam emitted by the laser is particularly vulnerable to human eyes, we have learned in this regard. A technician tune