Intersubband optical second-harmonic generation in multiple quantum wells: radiative coupling effects

An analysis of intersubband optical second-harmonic generation (SHG) in multiple quantum wells (QW's) is presented, in which special attention has been paid to radiative coupling effects. Starting from the Maxwell-Lorentz equations, the field at the second-harmonic frequency in the QW system is determined. Following the same framework, the field at the fundamental frequency is also obtained. In a reflection geometry, the SH conversion efficiency is derived for a p-polarized incident field. Detailed numerical calculations for different numbers of QW's, angles of incidence, as well as barrier thicknesses show that the SHG conversion efficiency can be significantly modified due to radiative coupling among wells.