Frequency stabilization of a Nd:YAG laser to Doppler-broadened lines of iodine near 532 nm

Diode-pumped Nd:YAG lasers are promising sources of the new optical frequency standards at 532 nm that were recommended recently in the 9th CCDM. Molecular iodine has several strong absorption lines at the second harmonic of Nd:YAG laser near 532 nm, thus providing an absolute reference for frequency stabilization. In general, the 532 nm laser sources used in iodine-stabilized systems are commercial monolithic lasers, which are compact, efficient, and reliable, but are also expensive and complicated. Recently, we have frequency stabilized a self-developed single-frequency Nd:YAG-KTP laser to the Doppler-broadened (instead of Doppler-free) lines of iodine. That was the first time to stabilize a 532 nm laser to an absolute reference in China. Due to its concise structure, low cost, and the ability to resist more disturbance, the laser system is attractive in some certain industrial applications that require an absolute frequency reference but not very high stability.