Stand-off Raman detection using dispersive and tunable filter based systems

Small, transportable Raman systems are being developed for stand-off Raman measurements at intermediate ranges (e.g. < 20 m) for planetary measurements. Four variations of stand-off Raman systems are described that use a small telescope for light collection that is either fiber-optic or lens-coupled to a detection system. The performance of an acousto-optic tunable filter for wavelength selection and spectral imaging is tested by comparing signal-to-noise ratio and throughput to similar measurements using a conventional spectrograph, and by measuring a variety of organic and inorganic mineral samples at distances up to 15 m. We also determine optimal ICCD gate widths for acquiring remote Raman spectra under high ambient light conditions. (c) 2005 Published by Elsevier B.V.