Abstract
Bragg diffraction from volume thermal gratings excited by crossed Gaussian laser beams provides a sensitive measurement of one- and two-photon absorption in fluid solution. The minimum detectable one-photon absorptivity (base e) was αmin = 1.0 × 10−6 cm−1 in a 3.3-nL probed volume, corresponding to the detection of 5 × 10−19 cm2. The two-photon cross section of benzene at 532 was determined by this technique to be 1.5 × 10−51 cm4 sec; detection of benzene two-photon absorption could be accomplished at concentrations as low as 6.4 × 10−4M. The method produces a diffracted signal on a zero background, so that detection of nonradiative relaxation of the sample is limited only by shot noise.
© 1985 Optical Society of America
Full Article | PDF ArticleMore Like This
W. T. White, M. A. Henesian, and M. J. Weber
J. Opt. Soc. Am. B 2(9) 1402-1408 (1985)
P. Horn, P. Braunlich, and A. Schmid
J. Opt. Soc. Am. B 2(7) 1095-1099 (1985)
S. L. Palfrey and T. F. Heinz
J. Opt. Soc. Am. B 2(4) 674-679 (1985)