High-stability diode-laser-based frequency reference at 1083 nm with iodine lines at 541.5 nm

Extended-cavity, fiber-amplified diode lasers at 1083 nm have been frequenc y stabilized by locking of their frequency-doubled radiation onto hyperfine components of I-2 at 541 nm by the frequency-modulation technique. The mea sured stability of 1.9 x 10(-12) at 1 s, improving to 4.1 x 10(-13) at 300 s, represents what are to the authors' knowledge the best results achieved for diode lasers at 1.08 mum. Experimental comparison with the previously u sed frequency reference for precise spectroscopy of He demonstrates a stabi lity improvement of similar to2 orders of magnitude. Preliminary results in He spectroscopy show significant reduction of frequency drifts and better precision as compared with previous measurements on He. (C) 2001 Optical So ciety of America.