We have studied the influence of cascaded second-order effects on the spectral density of a second-harmonic pulse generated in thin KDP and <i>β</i>-barium borate crystals by an intense femtosecond pulse. A noticeable evolution of spectral density is recorded for any value of phase mismatch. This evolution is in good agreement with the solution of the nonlinear propagation equation and allows a simple direct measurement of the effective susceptibility of the studied crystals.
© 1998 Optical Society of America
(120.4530) Instrumentation, measurement, and metrology : Optical constants
(190.2620) Nonlinear optics : Harmonic generation and mixing
(190.2640) Nonlinear optics : Stimulated scattering, modulation, etc.
(190.4400) Nonlinear optics : Nonlinear optics, materials
(320.2250) Ultrafast optics : Femtosecond phenomena
(320.7110) Ultrafast optics : Ultrafast nonlinear optics
S. Cussat-Blanc, R. Maleck Rassoul, A. Ivanov, E. Freysz, and A. Ducasse, "Influence of cascading phenomena on a type I second-harmonic wave generated by an intense femtosecond pulse: application to the measurement of the effective second-order coefficient," Opt. Lett. 23, 1585-1587 (1998)