We demonstrate a theoretical model and the experimental proof of a new method for n2 measurements using single pulses. The advantage of the method is fast measurement, a simple setup, and independence from small nonlinear absorptions and thermal effects. We report on first n2 measurements with the new technique on carbon disulfide, toluene, and a polymer dissolved in toluene to demonstrate the measurement of positive and negative third-order nonlinearities. We achieved a sensitivity of greater than λ/200 phase-front distortion using picosecond Nd:YLF laser pulses. The given theory shows that attainment of higher sensitivities is possible.
© 1997 Optical Society of America
Original Manuscript: April 16, 1996
Revised Manuscript: July 5, 1996
Published: February 20, 1997
J. Hein, M. Helbig, and S. Rentsch, "Measurements of a nonlinear refractive index with a single laser pulse," Appl. Opt. 36, 1173-1176 (1997)