Second-harmonic generation in rf sputter-deposited AlN thin films

The group III three metal nitrides are attractive candidates for short-wavelength applications in nonlinear optics because of their wide band gaps and their ease of fabrication by vapor deposition techniques. In this report the investigation of optical second harmonic generation (SHG) in AlN thin films is presented. AlN films were grown on the (0001) surface of sapphire substrates using the reactive rf magnetron sputtering technique. These films are optically transparent. Samples varying in thickness between 0.15 and 1 μm were fabricated and characterized by SHG studies. SHG measurements were carried out in the transmission mode using the 1.06 μm output of a Q-switched YAG laser. The dependence of sand p-polarized SHG on incident polarization and incident angle were used to determine the orientation and the magnitudes of the components of the χ tensor. Linear waveguide experiments have been performed and found to exhibit suitably low losses. Investigations of nonlinear waveguides are in progress.