Frequency Stabilization of Two Diode-Pumped Nd:YAG Lasers Locked to Two Fabry-Perot Cavities

We describe frequency stabilization of two laser-diode-pumped Nd:YAG lasers independently locked to two high-finesse Fabry-Perot cavities. The frequency noise (FM noise) is reduced to the shot noise limit of 0.37 mHz/√Hz at the error signal. A heterodyne beat note between two locked lasers is used to measure the frequency stability, and the beat linewidth of 16 Hz and the root Allan variance of 19 Hz at time interval of 3 ms are measured. We also measured an effect of angular ground vibration to FM noise. The sensitivity of 3.38 mHz/√Hz / nrad below 10 nradrms is obtained in our system.