High-stability diode-laser-based frequency reference at 1083 nm with iodine lines at 5415 nm

Extended-cavity, fiber-amplified diode lasers at 1083 nm have been frequency stabilized by locking of their frequency-doubled radiation onto hyperfine components of I2 at 541 nm by the frequency-modulation technique. The measured stability of 1.9×10-12 at 1 s, improving to 4.1×10-13 at 300 s, represents what are to the authors’ knowledge the best results achieved for diode lasers at 1.08 µm. Experimental comparison with the previously used frequency reference for precise spectroscopy of He demonstrates a stability improvement of ∼2 orders of magnitude. Preliminary results in He spectroscopy show significant reduction of frequency drifts and better precision as compared with previous measurements on He.