Temporal Properties of Ultrashort Laser Pulses in Photonic Lattice by SHG-FROG Technique

A second harmonic generation frequency-resolved optical gating(SHG-FROG)detection system was built for quantitatively analyzing the controlling of photonic lattice for ultrashort laser pulses in temporal and frequency domain and its nonlinear dynamic progress.The electric field in time domain,spectrum,and their phases were quan-titatively retrieved by the principal component generalized projection algorithm(PCGPA)from the FROG traces.The pulse duration,bandwidth,center wavelength,and the chirp of first 5 orders were obtained by numerical fitting,based on which,the influence of nonlinear phase shift and chirp on spectrum and the influence of dispersion and self-phase modulation(SPM)on duration were discussed.Results show that photonic lattice can control not only an electric magnetic wave spatially but also its properties in temporal and frequency domain and nonlinear dynamic progress flexibly.In the propagation process,the relationship between duration and spectrum is governed by dispersion,nonlinear coefficient,structure,and some other factors of the propagating system.