We report on measurements of the nonresonant third-order susceptibilities of the gases water vapor, n-butane, and propane. The susceptibilities were obtained from scanned coherent anti-Stokes Raman spectroscopy (CARS) spectra of binary gas mixtures containing N2 and each species of interest. The resonant susceptibility of N2, which served as a calibration standard for the measurements, was calculated using a modified exponential-gap model. Raman transition linewidths for the model were based on separate measurements by inverse Raman spectroscopy. We separately measured the nonresonant contributions from distant Raman transitions, predominantly C–H stretch modes. For parallel-polarized CARS configurations, the total effective nonresonant susceptibilities for propane, n-butane, and water vapor, respectively, were found to be 11.5 ± 1.4, 14.4 ± 1.8, and 2.2 ± 0.3 times that of N2 [using 8.5 × 10−18 (cm3/erg)/amagat].
© 1987 Optical Society of America
Original Manuscript: January 5, 1987
Manuscript Accepted: April 13, 1987
Published: August 1, 1987
R. L. Farrow, R. P. Lucht, and L. A. Rahn, "Measurements of the nonresonant third-order susceptibilities of gases using coherent anti-Stokes Raman spectroscopy," J. Opt. Soc. Am. B 4, 1241-1246 (1987)