Generation of dual-wavelength pulses by frequency doubling with quasi-phase-matching gratings

We demonstrate generation of two synchronized picosecond pulses at different wavelengths near 778 nm by frequency doubling of a femtosecond pulse. We use nonlinear frequency filter ing with quasi-phase-matching g ratings, which allow us to obtain second-harmonic spectral intensities that are higher than the spectral intensities of the pump.