Second-harmonic generation in polycrystalline pentacene films of submicrometer thickness by pulses of 18-fs duration is studied. We observe a second-order nonlinearity of as much as deff = 0.045 pm/V, which is resonantly enhanced at wavelengths near 790 nm. Off-resonance autocorrelation studies demonstrate a quasi-instantaneous nonlinear response of the material, whereas experiments on resonance point to a finite response time T2 of the order of 15 fs.
© 1996 Optical Society of America
Original Manuscript: October 16, 1995
Published: April 1, 1996
T. Jentzsch, H. J. Jüpner, S. H. Ashworth, and T. Elsaesser, "Second-order nonlinearities of polycrystalline molecular films studied on a 20-fs time scale," Opt. Lett. 21, 492-494 (1996)