Frequency Stabilization Of A 632.8nm He-Ne Laser Based On A Gas Capsule And A Glass-Ceramic Fabry-Perot Cavity

Since the appearance of the first laser in 1960 s, its frequency stabilization promptly drew great attention. With the development of laser technique and precise spectrum, the frequency stabilization gains a dramatic promotion and gets a far-ranging application in areas like optical communication, optical frequency standard, precision interference measurement and high resolution optical spectroscopy. People keep on finding new methods to lift the laser frequency stabilization while meeting different commands in practical use. The He-Ne gas laser has an early start in keeping its frequency stable, and has reached a rather high level of frequency stability. Among which the 632.8nm He-Ne laser that locks its frequency to the 1272 I saturated absorption lines has been chosen as one of the international frequency standards.This Research Project combines the practical application requirements and the advantage of processing technology in our laboratory, taking the resonant frequency of a high finesse glass-ceramic Fabry-Perot cavity as the frequency standard, and successfully locks the laser frequency to the Fabry-Perot cavity. In the meanwhile, by anatomizing the advantages and disadvantages of the piezoelectric ceramics in frequency stabilization, we came up with a new idea, which is using a gas capsule to change the refract ive index of the gas, and thus locking the laser frequency. This paper chooses the start point at the traditional method in locking the laser frequency, and gives some theoretical analysis in using the gas capsule method to lock the laser frequency as well as some simulations about the impacts of the environmental vibrations and temperature variations on the system.With a series of experiments, we finally reach the goal of successfully locking the frequency to the Fabry-Perot cavity resonant point with a frequency stability of the He-Ne laser by the order 10-10 for the sampling time of 10 seconds. In the meantime, we have compared the results of frequency stability for both methods: varying the laser cavity length and varying the gas refractive index through a serials of experiments. For some certain phenomena, we have shown the analysis and the corresponding confirmations. As for the shortcomings of the now available gas capsule method, we give some optimal designs at the end of this paper, which indicates unique superior in the frequency stabilization area for the gas capsule method.