Spatial gratings are recorded holographically by two femtosecond pump pulses at 388 nm in lithium niobate (LiNbO3) crystals and read out by a Bragg-matched, temporally delayed probe pulse at 776 nm. We claim, to our knowledge, the first holographic pump-probe experiments with subpicosecond temporal resolution for LiNbO3. An instantaneous grating that is due mostly to the Kerr effect as well as a long-lasting grating that results mainly from the absorption caused by photoexcited carriers was observed. The Kerr coefficient of LiNbO3 for our experimental conditions, i.e., pumped and probed at different wavelengths, was approximately1.0×10^−5 cm²/GW.
© 2005 Optical Society of America
(050.7330) Diffraction and gratings : Volume gratings
(190.3270) Nonlinear optics : Kerr effect
(190.4380) Nonlinear optics : Nonlinear optics, four-wave mixing
(190.7110) Nonlinear optics : Ultrafast nonlinear optics
Hung-Te Hsieh, Demetri Psaltis, Oliver Beyer, Dominik Maxein, Clemens von Korff Schmising, Karsten Buse, and Boris Sturman, "Femtosecond holography in lithium niobate crystals," Opt. Lett. 30, 2233-2235 (2005)