A simple frequency lock of green YAG laser to Doppler-broadened spectrum of iodine molecules utilizing an acousto-optic frequency shifter

A simple frequency stabilization method for frequency-doubled output (532 nm) of an Nd:YAG laser is described. The frequency shift caused by an acousto-optic modulator is effectively applied to stabilize the laser frequency. For the frequency stabilization, there are two kinds of error signal: (1) the first-derivative of absorption of iodine molecules and (2) the first-derivative of dispersion were extracted to examine which signal is suitable for the actual stabilization of the laser frequency. Based on this examination, the stabilization was executed utilizing the error signal (1), resulting in a frequency instability of .