AlN single crystals for photonic applications

The objective of proposed work is to demonstrate that AlN single crystals are suitable for nonlinear optical (NLO) and electro-optic (EO) applications in the visible and UV spectral ranges. AlN is a promising material for photonic applications that requireUV-compatibility, mechanical, chemical and optical robustness, as well as radiation hardness. As a non-centrosymmetric material, AlN has a 2nd order, non-linear susceptibility which yields macroscopic nonlinear optical and linear electro-optic properties.To date, these important optical properties have neither been systematically studied nor exploited for commercial photonic devices, but early experimental data, as well as theoretical work suggest that AlN features larger NLO coefficients than anycurrently available, UV-compatible NLO crystals. The proposed experimental investigation will evaluate the performance of AlN for electro-optic phase and amplitude modulation, as well as harmonic wave generation. The potential of AlN as a photonic materialin the visible and, primarily, in the UV spectral ranges is particularly exciting since nonlinear optical, AlN-based devices can easily be integrated with AlGaN-based electronics, heterojunction lasers, and detectors. Furthermore, AlN-based photonicbandgap structures (1D-PBGs) will considerably enhance nonlinearities and enable the design of novel photonic devices. AlN-based, nonlinear optical and electro-optic devices are anticipated to be compatible with UV applications to wavelengths as short as~ 200 nm. AlN is mechanically and chemically robust, and is anticipated to feature particularly high optical damage threshold due to its very large thermal conductivity. All these properties, as well as the ease of miniaturization and on-chip integrationwith III-nitride-based electronics and opto-electronics make AlN a superior nonlinear optical and electro-optical material for novel photonic applications, both in the military and commercial areas. Electro-optic applications include UV-compatible phaseand amplitude modulators and switches, while nonlinear-optical frequency-doubling using photonic bandgap structures will enable generation of UV light down to wavelengths of ~ 200 nm, which is desirable for future optical communication and data storage,as well as fluorescence-based, real-time detection of biological and chemical agents.