High performance iodine frequency reference for tests of the LISA laser system

Forthcoming space missions like the Laser Interferometer Space Antenna (LISA) or the Space-Time Asymmetry Research (STAR) project call for optical frequency references with high frequency stability better than 10
^-14
at averaging times longer than 1000 s. Since Nd:YAG lasers are planned to be used on these missions, new interest has arisen in the frequency stabilization of Nd:YAG lasers to hyperfine transitions in molecular iodine. Iodine stabilized lasers offer an absolute optical frequency reference with high frequency stability and low sensitivity to temperature fluctuations and magnetic fields in relative simple setups. Here we present our iodine frequency standard using modulation transfer spectroscopy with a multi-pass iodine cell showing a frequency stability of 1·10
^-14
at 1 s averaging time.