Recent Advances in Combined Standoff Laser-induced Breakdown Spectroscopy and Raman Spectroscopy
Monday, March 08, 2021: 2:40 PM - 3:15 PM
Various active optical spectroscopies capable of probing different energetic levels of matter could use a common instrumental set-up, if the spectral range and spectral resolutions are similar. In recent years, this has been developed through the combination of the standoff instruments for Laser-induced Breakdown Spectroscopy (LIBS) (which provides access to elemental information) and with Raman spectroscopy (which gives access to molecular information) for planetary exploration as well as for other terrestrial applications including mining, explosive detection, and work in harsh and remote environments. For planetary exploration integrated instruments for Raman and LIBS measurements have been miniaturized. However, the standoff range of detection of planetary instruments has been limited to less than 10 meters, and relatively high laser power (~10 mJ/pulse) is needed for measuring the standoff LIBS and Raman spectra of rocks and minerals. At the University of Hawaii, we have extended the range of both LIBS and Raman measurements of rocks and minerals to greater than 200 m using low laser power (3 mJ/pulse) of a pulsed 532-nm laser. The combined LIBS and Raman instrument is mounted on a stationary platform and a small remotely operated rover carries a 45-degree mirror and a focusing lens for exciting the LIBS and Raman spectra of samples. These advances in the combined LIBS and Raman instrumentation will be very useful for planetary exploration including the frozen volatiles (e.g., water-ice, gas hydrated etc.) in the permanently shadowed region of the Moon and even Europa with a lander accompanying a small rover. These technological advances will also allow detection of both the elemental composition and molecular structure of hazardous chemicals used in home-made explosive devices (HMEs) from a safe distance. Potential applications of the LIBS-Raman system for planetary exploration, homeland security, and defense will be discussed.
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Hyphenated Techniques - Other,Instrumentation,Raman/Surface Enhanced Raman Spectroscopy,Spectroscopy