Measurement of acetylene-d absorption lines with a self-referenced fiber laser frequency comb

A self-referenced optical frequency comb, derived from a mode-locked fiber laser, and a cavity-enhanced diode-laser-based saturated absorption spectrometer were employed to measure the absolute frequency of 55 absorption lines of the P and R branches of the 2ν1 band of 12C2HD at 1.5 μm with a one standard deviation uncertainty of better than 2.5 kHz for all lines measured. The shift sensitivities of the P(16) line to changes in power, pressure, and modulation amplitude have been studied in detail. Improved values of the ground-state molecular constants are obtained.