激光相位调制法布里-珀罗腔精细度法测定反射率

谐振腔精细度法是通过测量光学谐振腔透射谱线宽度来实现对光学反射镜反射率的测定。由于此谱线宽度数值通常在射频范围,采用光谱仪难以精确测量,而在谐振腔精细度方法的基础上引入激光相位调制技术,提出激光相位调制法布里-珀罗(F-P)腔精细度法测定反射率。利用电光调制器对激光进行射频相位调制,以产生的调制边带与激光载波的频率间隔作为“射频标尺”,精确测量了法布里-珀罗腔透射光谱的谱线宽度。利用腔精细度与腔透射光谱的谱线宽度及反射率的关系公式,获得了反射镜的反射率,测量精度可达到10-4。

Measurement of Reflectivity of Optical Mirrors Using Laser Phase Modulation and Fineness of Fabry-Perot Cavity

The reflectivity of optical mirrors can be obtained by measuring linewidth of transmission spectrum of optical cavity and the fineness of Fabry-Perot (F-P) cavity. It is difficult for a spectrometer to measure the linewidth accurately due to its limited resolution. In this paper, laser phase modulation is introduced on the basis of fineness of F-P cavity, and laser phase modulation and fineness of F-P are proposed for measuring the reflectivity of optical mirrors. The frequency interval between the carrier and one sideband generated by electro-optical modulation is used as a radio frequency ruler to precisely measure the linewidth. Thus the reflectivity of mirrors is obtained with uncertainty reaching the level of 10 -4 by the relation of fineness of cavity, spectral linewidth and reflectivity of mirrors.