We demonstrate precise optical frequency-difference measurement of acetylene (C2H2) absorption lines at 1.5 µm. With an optical comb generator, the frequency difference between two lasers locked to saturated absorption dips of C2H2 rovibrational lines can be measured up to ~1 THz with a precision of better than 100 kHz. A precise frequency table of C2H2 1.5-µm lines will be useful for frequency-division-multiplexed optical communication systems and high-resolution molecular spectroscopy.
© 1995 Optical Society of America
K. Nakagawa, M. de Labachelerie, Y. Awaji, M. Kourogi, T. Enami, and M. Ohtsu, "Highly precise 1-THz optical frequency-difference measurement of 1.5-µm molecular absorption lines," Opt. Lett. 20, 410-412 (1995)