Measurement Of Reflectivity Of Optical Mirrors Using Laser Phase Modulation And Fineness Of F-P Cavity

Measurement of reflectivity of optical mirrors is useful not only to improve techniques of coating but also to advance quality of films. With the development of laser technology, methods of measuring reflectivity of optical mirrors are developing rapidly. Recently the request of measuring the reflectivity of optical multi-film and the need of high reflectivity of mirrors for optical cavity have promoted the development of the technique of measuring reflectivity of mirrors.A new method presented in this paper is discussed around the study of measuring reflectivity of mirrors.First, principles, characteristics and applications of common methods are explained.Second, laser phase modulation is introduced into the method of fineness of optical cavity, then a new method called laser phase modulation and fineness of F-P cavity is proposed ,and this method can solve the difficulty that linewidth of spectrum of F-P cavity can not be measured accurately by previous ways . The principle and setup of experiment are explained in detail. Some factors that influence the accuracy of measuring reflectivity are discussed , and relevant steps for improving the experiment are given .Thus, the reflectivity of mirrors is obtained, and its uncertaintity is at the 10^-4 level.Finally, applications of the new method are discussed .