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The Perseverance rover landed in Jezero crater, Mars, in February 2021. We used the Scanning Habitable Environments with Raman and Luminescence for Organics and Chemicals (SHERLOC) instrument to perform deep-ultraviolet Raman and fluorescence spectroscopy of three rocks within the crater. We identify evidence for two distinct ancient aqueous environments at different times. Reactions with liquid water formed carbonates in an olivine-rich igneous rock. A sulfate-perchlorate mixture is present in the rocks, which probably formed by later modifications of the rocks by brine. Fluorescence signatures consistent with aromatic organic compounds occur throughout these rocks and are preserved in minerals related to both aqueous environments.

We describe the wavelength calibration of the spectrometer for the scanning of habitable environments with Raman and luminescence for organics and chemicals (SHERLOC) instrument onboard NASA's

Due to its high sensitivity and selectivity, UV resonance Raman (UVRR) spectroscopy has a number of scientific and industrial applications. Deep UVRR excited within explosive absorption bands (200 – 230 nm) enables trace explosive detection at a distance due to the resonance enhancement of Raman band intensities, stronger light scattering at short wavelengths, as well as negligible florescence interference. We are developing deep UVRR detection methodologies by investigating resonance enhancement of explosives excited in the deep UV, determining the optimal excitation wavelengths, investigating explosive UV-photochemistry, characterizing explosive UV photoproducts, and measuring UVRR spectral evolution during explosive photolysis. We are also developing state-of-the-art UVRR instrumentation by designing and manufacturing high efficiency, high throughput standoff UVRR spectrometers, co-developing new compact solid state deep UV lasers, and designing novel deep UV optical diffracting devices.

We describe the wavelength calibration of the spectrometer for the scanning of habitable environments with Raman and luminescence for organics and chemicals (SHERLOC) instrument onboard NASA’s Perseverance Rover. SHERLOC utilizes deep ultraviolet Raman and fluorescence (DUV R/F) spectroscopy to enable analysis of samples from the Martian surface. SHERLOC employs a 248.6 nm deep ultraviolet laser to generate Raman-scattered photons and native fluorescence emission photons from near-surface material to detect and classify chemical and mineralogical compositions. The collected photons are focused on a charge-coupled device and the data are returned to Earth for analysis. The compact DUV R/F spectrometer has a spectral range from 249.9 nm to 353.6 nm (∼200 cm−1 to 12, 000 cm−1) (with a spectral resolution of 0.296 nm (∼40 cm−1)). The compact spectrometer uses a custom design to project a high-resolution Raman spectrum and a low-resolution fluorescence spectrum on a single charge-coupled device. The natural spectral separation enabled by deep ultraviolet excitation enables wavelength separation of the Raman/fluorescence spectra. The SHERLOC spectrometer was designed to optimize the resolution of the Raman spectral region and the wavelength range of the fluorescence region. The resulting illumination on the charge-coupled device is curved, requiring a segmented, nonlinear wavelength calibration in order to understand the mineralogy and chemistry of Martian materials.