Second Harmonic Generation in Periodically Poled GaN

We report the first experimental demonstration of second harmonic generation in periodically poled GaN by first-order quasi-phase matching. The periodically poled structure was grown by plasma- assisted molecular beam epitaxy. We observed about 9 mW of second harmonic power from a fundamental input laser wavelength of 1658.6 nm with a normalized conversion efficiency of 12. 76 % W-1cm-2. The ability to perform nonlinear wavelength conversion by periodic poling and the fact that GaN has a very wide window of transparency, pave the way for GaN to be used for nonlinear optical devices in telecommunications as well as a nonlinear light source for biochemical detection in the far infrared and deep ultraviolet.