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-poweracceptance 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 4.2x10(-5) Hz/ radicalHz below the Fourier frequency of 500 Hz.