Giant third-harmonic in porous silicon photonic crystals and microcavities

Abstract

In recent years, the nonlinear optics of photoniccrystals (PCs) and PC-based microcavities (MCs) hasbeen progressing intensively [1]. Giant nonlinear-opti-cal phenomena caused by giant effective dispersion atthe edges of the photonic band gap and in the vicinityof the cavity mode, and also by the enhancement ofoptical fields inside PCs and MCs under optimal fre-quency–angular conditions, can be observed in suchmicrostructures. In particular, multiple reflection inter-ference in PCs can compensate the phase mismatch forfundamental and second-harmonic waves when one ofthe waves falls on the edge of the photonic band gap inthe space of frequencies or wave vectors [2]. Such aneffective fulfillment of the phase matching conditionsleads to a resonant enhancement of second-harmonicgeneration in PCs composed, for example, of dielectricpolystyrene spheres [3], alternate GaAs–AlGaAs [4] orZnS–SrF