INCREASING THE FREQUENCY STABILITY OF SINGLE-FREQUENCY LASERS

We have developed an improved technique to increase the stability of s ingle-frequency lasers by employing a scanning Fabry-Perot interferome ter and a stabilized helium neon laser. Our instrument surpasses earli er devices in several key areas. The laser frequency can now be stabil ized while scanned across its inherent single-frequency tuning range. The frequency stability is long term with an increased frequency corre ction rate of nearly 500 Hz. The laser frequency can be scanned repeat edly with a repetition accuracy equal to the frequency stability. Also , the electronics permit the laser frequency to be swept externally wh ile synchronized with other instruments. Our stabilizer reduced the fr equency drift of a commercial ring dye laser to +/- 1 MHz relative to the reference laser.