Deep UV Semiconductor Sourcess for Advanced Planetary Science Instruments

This proposal addresses the need for miniature deep UV light sources that operate at very low ambient temperatures without heating or temperature regulation for use in advanced in situ planetary science instruments involved in the reagent-less detection and identification of trace amounts of organic, inorganic, and biogenic materials. The proposed sources are aluminum gallium nitride (AlGaN) semiconductor lasers and light emitting devices emitting between 210 nm to 250 nm, a spectral range which has been demonstrated to provide higher detection sensitivity and chemical differentiability than sources emitting at longer wavelengths. Instrument applications include non-contact, robot-arm or body mounted, reagentless chemical imaging instruments and detectors for analysis of chemical extractions from soil, rock, or ice employing non-contact, non-destructive native fluorescence and/or resonance Raman spectroscopic methods. The proposed semiconductor source approach avoids the problems that continue to limit emission wavelengths of semiconductor lasers to wavelengths above 340 nm. Using free electron injection we have demonstrated internal quantum efficiencies over 100 times higher than reported elsewhere. It is the goal of this program to demonstrate deep UV laser emission from a semiconductor device less than 250 nm using the proposed approach. This will lead to miniature, high efficiency, TRL 4 devices.