Accurate optical frequency atlas of the 1.5-mu m bands of acetylene

We have measured the absolute optical frequencies of 90 rovibrational lines of the (C2H2)-C-12 and (C2H2)-C-13 1.5-mu m bands. Using an optical frequency comb generator, we could precisely measure the relative frequencies between two lasers stabilized on the saturation dip of the rovibrational lines up to 2 THz apart. The absolute frequencies were determined with respect to the Rb two-photon transition at 0.778 mu m with a HCN rovibration line at 1.556 mu m used as an intermediate reference. This measurement provides an accurate frequency atlas of acetylene 1.5-mu m bands with an uncertainty of similar to 10(-9). (C) 1996 Optical Society of America.