Frequency Doubling Of Femtosecond Laser Pulses In Nonlinear Photonic Crystals With Account Of High-Order Dispersion

We studied numerically the frequency doubling of femtosecond laser pulses (up to ∼ 5 fs) in nonlinear photonic crystals. We investigated the impact of a number of factors (phase modulation of the primary emission pulse and spatial modulation of nonlinear susceptibility, up to the third order dispersion of a nonlinear photonic crystal) on the efficiency of nonlinear conversion and the duration of the secondharmonic pulse. We show that the efficiency of second-harmonic generation reaches η 2 ω ∼ 45% when ultrashort (down to 5 fs) laser pulses are used.