High-frequency-stability diode-pumped Nd : YAG lasers with the FM sidebands method and Doppler-free iodine lines at 532 nm

The FM spectroscopy technique has been applied to two frequency-doubled Nd:YAG lasers-to achieve absolute frequency stabilization against the hyperfine structure components of the rovibronic P(54) 32-0 iodine line at 532 nm. A fractional frequency stability of 2 x 10(-13) tau(-1/2) has been obtained for integration times in the range of 1 ms < tau < 10 s. For longer integration times the stability level remains below 10(-13), reaching a minimum value of 4.6 x 10(-14) at 100 s. This high stability level is, to our knowledge, the best value achieved against iodine lines by this locking method and for a fully transportable system. (C) 1999 Optical Society of America. OCIS codes: 120.3930, 120.3940, 120.4800, 300.6320, 020.2930.