Piezoelectrically-enhanced 230 nm far-UV second harmonic generation in a polarity-inversion-free AlN/AlGaN strained-layer superlattice channel waveguide

Abstract

Far-ultraviolet (UV) light has a wide range of global applications, including virus inactivation, bacterial disinfection, human body sterilization, communication, and sensing. Nitride semiconductors, such as AlN and AlGaN, are particularly advantageous for wavelength conversion applications because of their large energy bandgap of approximately 6 eV, which provides excellent transparency in the far-ultraviolet spectrum. In this study, we employed a transverse-quasi-matching approach to design and fabricate an AlN/AlGaN strained-layer superlattice (SLS) channel waveguide. The wavelength spectra and power dependency of the SH intensity confirm the first successful demonstration of far-UV light emission from a polarity-inversion-free SLS structure via the enhancement of the second-order nonlinear optical susceptibility by piezoelectric polarization under ultrashort pulse stimulation.