Photorefractive effect during propagation of ultrashort laser pulses in LiNbO3:Ti optical waveguides

The photorefractive effect was observed experimentally during propagation of λ=0.53μ ultrashort laser pulses in LiNbO₃:Ti waveguides. The photorefractive effect accumulated over 10³ ultrashort pulses each having an energy ~10^–5J. An investigation was made of the influence of the photorefractive effect on second harmonic generation during propagation of λ=1.055μ ultrashort pulses in waveguides. Experiments were carried out on the photorefractive recording of holographic gratings in waveguides exposed to cw (λ=0.51 and 0.63μ) and ultrashort pulse radiation (λ=0.53μ). Possible reasons for the differences observed in the appearance of the photorefractive effect in these cases are discussed.