Deep UV Lasers for Raman & Fluorescence Spectroscopy in Extreme Environments

This proposal addresses the need for next generation deep UV (NGDUV) lasers for detection and spatial chemical mapping of trace amounts of organic, pre-biotic, or biological material as well as inorganic compounds and water embedded in a mineral matrix using non-contact deep UV resonance Raman and native fluorescence spectroscopy.nbsp; Detection of these materials and their spatial distribution within a mineral matrix are fundamental capabilities required to meet NASA strategic goals. Benefits of this method have been demonstrated on the Mars 2020 SHERLOC instrument, which successfully landed on Mars on 18 February 2021.nbsp; NGDUV lasers address the need of increasingly miniaturized next generation chemical and biological detection instruments for deep UV Raman and fluorescence detection in extreme environments including lander missions to Titan and other ocean worlds with temperatures of -200 0C, or below, as well as shadows on the Moon, asteroids, comets, and other small bodies.nbsp;Specifications for a deep UV laser for operating in these extreme environments, with the performance and size, weight, and power consumption compatible with these missions, was studied as part of the Mars Perseverance SHERLOC development.nbsp; The prospect for suitable lasers includes a long list of laser types, each of which has a long history of development and different potential for applicability.nbsp; Fundamental to all laser types is the need for an excitation wavelength below 250 nm to minimize fluorescence background from targeted samples and enable unambiguous Raman and fluorescence spectra of simple organic molecules.nbsp; The second requirement is for a laser emission linewidth and line stability, independent of ambient temperature less than about 0.01 nm. The laser types which could potentially satisfy these needs includes semiconductor, fiber, solid state, and gas lasers.nbsp; Each of these laser types will be evaluated and a path forward proposed for the most likely prospects.nbsp;