Phase-matched second harmonic generation in asymmetric double quantum wells

Abstract

Efficient (∼1%) second harmonic generation, resonantly enhanced near λ=8.6 μm, has been observed in asymmetric double multi-quantum well structures. We used (i) edge-emitting waveguide geometry where the phase matching was achieved by incorporating a separate multiple quantum well region which modifies (via the Kramers–Kronig relation) the dispersion of light and (ii) 45° wedge multi-bounce geometry where the phases of second harmonic waves generated at sequential bounces were synchronized by changing the angle of incidence.