ASTID

Deep UV Semiconductor Laser for In Situ Detection and Classification of Trace Amounts of Organic, Prebiotic and Biological Materials on Mars (2)

PI: William Hug

Ultraviolet laser induced native fluorescence (UVLINF) and UV resonance Raman spectroscopy (UVRRS) are instrumental methods that hold great promise as miniature, rugged, light weight, low power consumption, in situ, micro-sensors for detection of important organic and geobiological chemicals on missions to Mars, Europa, Titan, and comets as well as for a wide range of terrestrial research applications. Deep UV lasers are one of the largest and most inefficient of the components in present micro-sensors. A deep UV semiconductor laser would enable significant miniaturization of UVLINF and
UVRRS micro-sensors, and have a dramatic immediate effect on the design of Rover-arm-borne organic micro-sensors. Photon Systems proposes to develop and demonstrate a deep UV semiconductor laser source emitting in the 225nm to 250nm spectral range for use in a wide variety of in-situ UVLINF and UVRRS point detection and chemical imaging micro-sensors to detect and identify trace amounts of chemical signatures of life, prebiotic
compounds, polyaromatic hydrocarbons (PAHs), other organic molecules, bound and free water, and minerals. Present wide band gap P-N junction semiconductor lasers have been unable to provide emission below about 340nm. The principal problems have been the inability to make high aluminum-content AlGaN semiconductor materials sufficiently conductive and the inability to make ohmic contacts to these materials. Our proposed
approach avoids these problems by generating electron-hole pairs in the active region of a high aluminum content AlGaN semiconductor film using a subminiature ballistic electron beam. Using this technique, we have previously demonstrated stimulated emission from an AlGaN semiconductor device at a wavelength as low as 240nm. In addition, we have demonstrated LED emission as low as 233nm. Based on data to date we believe our approach has a very high probability of success.