ULTRAHIGH-FREQUENCY STABILIZATION OF A DIODE-PUMPED ND-YAG LASER WITH A HIGH-POWER-ACCEPTANCE PHOTODETECTOR

We describe the ultrahigh-frequency stabilization of a diode-pumped Nd:YAG laser by use of a high-power-acceptance photodetector. The photodetector, which is constructed with an optical power divider and eight combined photodiodes, is developed to reduce shot-noise-limited FM noise. The laser frequency is locked to a Fabry-Perot cavity with a finesse of 25,600 by the Drever-Hall technique. By using the optical power of 47 mW at the photodetector, we reduce the relative FM noise at the error signal to the shot-noise limit of 42x10(-5) Hz/square-root Hz below the Fourier frequency of 500 Hz.