衍射极限倍因子M2的实验测量

目的测量He—Ne激光器（波长632．8nm）和半导体激光器（波长650nm）的肘。因子。方法根据ISO／TC172／SC9／WG1 N80文件对M^2因子的测量原理及要求，用美国Spirieon公司生产的LBA-300PC激光束分析仪，沿光传播方向在不同z位置，测出光束宽度，由测量数据进行双曲线拟合，确定束腰直径和远场发射角，计算M^2因子。结果所测全内腔玻璃外壳He—Ne激光器的M^2=1．422，半导体激光器的M^2=1．599。结论市场上流通的He—Ne激光器和廉价的半导体激光器大都可以用于医学应用，不适于用作干涉计量或全息照相等方面的应用。

Experimental measurement of times-diffraction-limit factor M2

Aim To measure M2 factors of semiconductor lasers and He-Ne lasers. Methods According to the document of ISO/TC 172/GW1 N80 about the test principle and the experimental demands of times-diffraction-imit factor M2,beam diameters in different z places along the light direction were measured using LBA-300PC laser beam quality analyzing meter made in Spiricon Corporation of America. Hyperbolas were fitted utilizing the measured data. Beam widths and divergence angles were determined, and M2 factors of the measured lasers were calculated. Results The measured He-Ne laser with full internal cavity and glass tube: M2=1.422, the measured semiconductor laser: M2= 1.559. Conclusion A majority of He-Ne lasers and cheap semiconductor lasers on the market can be used in medicine, but are not suitable in interference measurement and holographic imaging, etc.