Phase and group synchronization in second-harmonic generation of ultrashort light pulses in one-dimensional photonic crystals

It is shown, on the basis of an analysis of the dispersion relation for an infinite one-dimensional periodic multilayer structure and direct numerical integration of Maxwell's equations by the finite-difference method, that structures with photonic band gaps (PBGs) make it possible to provide simultaneously conditions for phase and group synchronizations for second-harmonic generation with participation of extremely short light pulses. The phase and group detunings, which arise as a result of the dispersion of the nonlinear medium, are compensated by the dispersion of the PBG structure. The use of this regime of nonlinearly optical interactions opens up the possibility of attaining high frequency conversion efficiencies irrespective of the synchronization length in the interior volume of a nonlinear material. (C) 2000 MAIK "Nauka/Interperiodica".