NONLINEAR FREQUENCY CONVERSION IN RAMAN ACTIVE CRYSTALS IN THE IMPULSIVE REGIME
B.I.Stepanov Institute of Physics , Belarus, France
We discuss experimental data on nonlinear conversion of 50 fs and 13 fs laser pulses in the Raman active crystals. As soon as the length of laser pulses is compared, or shorter than period of Raman active molecular vibrations this conversion is realized in the impulsive regime. Bessel beam geometry is used to suppress Kerr effect and avoid usual white light generation . Broadband axial pulses significantly exceeding pump are observed.