Absolute frequency stabilization of an extended-cavity diode laser against Doppler-free (H2O)-O-17 absorption lines at 1.384 mu m

We report the frequency stabilization of a cw extended-cavity diode laser against saturated absorption lines of the (H2O)-O-17 isotopologue of water vapor at around 1.384 mu m. The saturation of rotovibrational transitions is achieved by filling a high-finesse optical resonator with (H2O)-O-17 at low pressure and by locking the laser frequency to the resonator by using the Pound-Drever-Hall technique. Absolute frequency stabilization is obtained, locking the cavity resonance to the center of the sub-Doppler line by means of the wavelength modulation method. A relative frequency stability of sigma(tau)=10(-13)(0.1 tau(-2)+0.9)(1/2) is demonstrated for integration times in the range 4 ms <tau<30 0 s. (C) 2009 Optical Society of America