Second-Harmonic Generation in III-Nitride Quantum Wells Enhanced by Metamaterials

We report the results of theoretical investigation showing considerable enhancement of second harmonic generation (SHG) in multiple, asymmetric step GaN/AlGaN quantum wells (QWs) coupled to arrays of split ring resonators at mid-infrared frequencies. Simulations with a finite-difference time-domain (FDTD) method predict the highest SHG conversion factor about 11.2 W/
²
with a dramatically low pump intensity of ~5 W/cm
²
under normal incidence at 29 THz.Our results show that about three orders of magnitude in source power can be obtained by using III-nitride QWs instead of similar GaAs-based structures. The results imply that the combination of III-N QWs and metamaterials can be used for ultra-efficient SHG applications without any constraint in pump wave incident angle.