Abstract

We report observing Raman-shifted oscillation within a ring cavity containing cesium vapor and pumped with the output of a single-frequency diode laser tuned near the D₂ line. The oscillation is shifted from the diode-laser pump frequency by ≃9 GHz, the hyperfine splitting of the 6S_1/2 ground state of cesium. Many different transverse modes of oscillation are observed for slight variations in the cavity alignment. In addition, the oscillation is observed to turn on and off at 60 Hz as a result of the pump-frequency fluctuations associated with the line noise on the diode-laser drive current. The pump-frequency fluctuations (≃10 MHz) are small compared with the free spectral range (175 MHz) of the ring cavity. These characteristics indicate that the Raman oscillation in cesium vapor is narrow-band, similar to the behavior observed in sodium vapor.¹–³ As little as 30 mW of pump power is required for oscillation when highly reflective cavity optics are used. We have obtained 0.5 mW of Raman-shifted output with an appropriate output coupler at 65 mW of pump power.

© 1992 Optical Society of America