Second harmonic generation in doubly resonant planar microcavities

Second harmonic generation in planar microcavities is theoretically investigated and a new structure is proposed in order to achieve enhancement of the nonlinear process taking advantage of double resonance. In this case, both the pump and the harmonic field are resonant to photonics modes of the microcavity and a quasi-phase matching condition is satisfied simultaneously. The second harmonic generated intensity grows exponentially with the number of periods N in the dielectric mirrors as it happens for a single resonant microcavity. Example are given for AlGaAs/Alox dielectric mirrors where all the calculations are performed taking into account the material dispersion and neglecting the pump depletion.