Frequency stability improvement of a two-mode stabilized 633-nm He-Ne laser

摘要

The red side (lower-frequency) mode of a two-mode stabilized 633-nm He-Ne laser has been locked to the hyperfine structure of the P(33) line of r↑(127)I↓(2) by means of frequency modulation spectroscopy enhanced by an external optical cavity. Both the red side and blue side (higher-frequency) modes of the laser exhibit a frequency stability of 2.3 >4 10↑(－11)↓( T)↑(－1/2). In addition, the frequency fluctuations of the blue side mode are detected by a Fabry-Perot cavity and compensated through an acousto-optic frequency shifter. The short-term stability of better than 3×10↑(－11) is attained for integration times of between 2 × 10-a and 2×10↑(－3).# 1998 Optical Society of America OCIS codes: 140.3460, 300.6460, 300.6380.