Frequency stabilization of 633-nm He-Ne laser by using frequency modulation spectroscopy of127I2 enhanced by an external optical cavity

Abstract

The oscillation line from a two‐mode stabilized inner‐mirror‐type 633‐nm He‐Ne laser was locked to the iodine saturated absorption line. FM spectroscopy was used to detect the saturated absorption signal. An iodine cell was placed within the ring cavity to multiply the excited light. When the oscillation line on the red side (long‐wavelength side) of the two‐mode stabilized laser was locked to the 6‐3 band P(33) transition a‐component of 127I2/ the degree of frequency stabilization measured from the Allan variance σ(2, τ) was 2.3 × 10−11 × τ−1/2 on either the red or blue side. Under this condition, the nonmodulated optical power on the blue side was 1.3 mW. In addition, the dependence of the frequency shift of the P(33) transition a‐component on iodine vapor pressure and the frequency separations of oscillations for a to j components were measured. © 2000 Scripta Technica, Electron Comm Jpn Pt 2, 83(3): 1–9, 2000