Spatial Heterodyne Raman Spectroscopy for Planetary Surface Exploration. Egan, Miles J.
dc.contributor.department Chemistry 2019-05-28T19:40:48Z 2019-05-28T19:40:48Z 2017-05
dc.subject spatial heterodyne spectrometer
dc.subject Raman spectroscopy
dc.subject Fourier transform
dc.subject Raman
dc.subject interferometry
dc.subject mineralogy
dc.title Spatial Heterodyne Raman Spectroscopy for Planetary Surface Exploration.
dc.type Thesis
dcterms.abstract Raman scattering is a phenomenon characterized by the inelastic scattering of light by a molecule that has a normal mode of vibration capable of producing an instantaneous induced dipole moment when radiation is incident upon said molecule. The activity of vibrational modes in the Raman spectrum can be predicted via group theory by first identifying all the symmetry elements of a molecule or mineral, classifying said molecule into a point or space group, followed by removal of superfluous degrees of freedom and finally disambiguation of the vibrational degrees of freedom into irreducible representations. A vibrational mode is active in the Raman (IR) spectrum if the vibrational mode, as represented by an irreducible representation, contains a change in polarizability (change in dipole moment). In recent years, advancements in the speed, sensitivity and size of excitation sources, spectrographs and detectors has allowed the application of Raman spectroscopy to transition from delicate laboratory instruments to rugged in-situ spectrometers. The advancement in Raman instrumentation has simultaneously expanded the potential applications of Raman spectroscopy, which now ranges from pharmaceutical drug quality control to explosives detection to geological analysis on planetary surfaces. One of the most promising innovations in the field of Raman spectroscopy is the development of the spatial heterodyne Raman spectrometer (SHRS). SHRS is a variant of a Michelson interferometer in which the mirrors of a Michelson are replaced with two stationary diffraction gratings. When light enters SHRS, it is reflected off the diffraction gratings at frequency dependent angles that in turn produce crossed wavefronts in space that can be imaged by a plane array detector. The crossed wavefronts, which represent a superposition of interference fringes, are converted to a Raman spectrum upon Fourier transformation. This thesis is divided into four parts. In Chapter 1, the historical evolution of the theory and instrumentation of Raman spectroscopy is covered in detail. In Chapters 2 and 3, SHRS is used to measure the Raman spectra of materials of importance to planetary science exploration at standoff distances. Finally, in Chapter 4, the author takes account of the lessons learned from the preceding chapters and recommends some future work.
dcterms.description M.S. Thesis. University of Hawaiʻi at Mānoa 2017.
dcterms.language eng
dcterms.publisher University of Hawaiʻi at Mānoa
dcterms.rights All UHM dissertations and theses are protected by copyright. They may be viewed from this source for any purpose, but reproduction or distribution in any format is prohibited without written permission from the copyright owner.
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