Surface-emitting second-harmonic generator by intersubband transition in asymmetric quantum wells with slab waveguide

Abstract
We report the first experimental evidence of second‐harmonic generation due to intersubband transitions in GaAs‐Ga1−xAlxAs step multiquantum wells with a waveguiding surface‐emitting structure. The second‐harmonic generation signal obeys wave vector conservation and propagates perpendicular to the waveguiding surface. As high as 3×10−3 power conversion efficiency has been obtained. The experimental analysis and the severalfold benefit of this novel technique have been given in detail.