Quantum interference in the rate of two-photon excitation of the 6S½ →6P3/2 → 6D5/2 transition in atomic cesium is exploited to demonstrate phase-sensitive frequency demodulation for an optical interval of ± 12.5 THz. By thus using atoms as ultrafast nonlinear mixing elements, we suggest and analyze a new avenue for absolute comparisons of a dense set of frequencies over the range of 200–2000 nm.
© 1996 Optical Society of America
N. Ph. Georgiades, E. S. Polzik, and H. J. Kimble, "Frequency metrology by use of quantum interference," Opt. Lett. 21, 1688-1690 (1996)