A large improvement in the frequency stability of a single-mode cw dye laser has been obtained1 by using a wide-band (0–100 kHz) servo system to lock the dye laser frequency to a transmission fringe of a high-finesse optical cavity. By applying corrections to the optical length of the dye laser cavity, the free-running laser stability of ±50 MHz (for one second averaging time) was reduced to drifts of about 1 – 2 MHz/minute (corresponding to controllable drifts of optical cavity temperature and possibly of optical coupling parameters). The frequency has been made to track these drifts in a single cavity with errors less than 50 kHz rms for short times (20 µsec) and less than 100 Hz for long times (10 sec ).
KeywordsFrequency Stability Optical Cavity Servo System Frequency Discriminator Allan Variance Plot
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