2-PHOTON COHERENT-TRANSIENT MEASUREMENT OF THE NONRADIATIVE COLLISIONLESS DEPHASING RATE IN SF6 VIA DOPPLER-FREE DEGENERATE 4-WAVE MIXING

This Letter reports, for the first time, an experimental measurement of the collision-less dephasing time of the ν3=2 level in SF6 using Doppler-free two-photon degenerate four-wave mixing. The measurement is performed in the time domain by use of a short-pulse CO2 laser to establish a molecular two-photon coherent state. The coherent state is then probed as a function of time to yield a dephasing time of 1.8 nsec which is related to intramolecular dephasing rates. © 1979 The American Physical Society.