We have employed dye-laser pulses of 10-nsec duration and 1.5-10-nm bandwidth in a transient four-wave-mixing experiment to study high-perturber-pressure collisional dephasing in dilute atomic sodium vapor. Working at argon perturber pressures of several atmospheres, we are able clearly to resolve dephasing times over a thousand times shorter than our excitation pulse duration. Measured dephasing rates are in excellent agreement with those measured by more traditional methods. When both of the sodium D lines are excited, our signal displays quantumbeat-like oscillations at the 0.52-THz frequency difference between these two states. We provide a simple picture explaining the origin of these beats.
© 1986 Optical Society of America
J. E. Golub and T. W. Mossberg, "Studies of picosecond collisional dephasing in atomic sodium vapor using broad-bandwidth transient four-wave mixing," J. Opt. Soc. Am. B 3, 554-559 (1986)