Deep UV Semiconductor Sources for Advanced Planetary Science Instruments

This proposal addresses the need for miniature, narrow-linewidth, deep UV optical sources that operate at very low ambient temperatures for use in advanced in situ planetary science instruments for non-contact detection and classification of trace amounts of organic, inorganic, and biogenic materials using Raman and native fluorescence spectroscopic methods. The sources include aluminum gallium nitride semiconductor lasers and ultra-narrow-linewidth transverse excited hollow cathode lasers emitting between 210 nm to 250 nm, a spectral range with demonstrated higher detection sensitivity and specificity than sources emitting at longer wavelengths. Applications include non-contact robot-arm or body mounted chemical imaging instruments and detectors for direct analysis of trace levels of chemical species containing C, N, H, O, S, Cl, on surfaces or as extractions from soil, rock, or ice. We have achieved the highest recorded deep UV semiconductor internal quantum efficiencies at wavelengths below 250 nm. But continuing difficulties of attaining laser emission and prospects for narrow line-width compatible with Raman applications has caused us to redirect a significant portion of the Phase II effort to another class of deep UV laser with a more proven UV Raman track record and the potential for miniaturization for robot-arm-mounted applications.