This Small Business Innovation Research Phase I project will develop an ultra-narrowband liquid crystal tunable filter (LCTF) as the basis of a Raman chemical imaging microscopy station for non-invasive chemical characterization of solid-state materials. The advantages in performance and practicality provided by this technique will allow Raman chemical imaging to become a mainstream analytical methodology for the first time, accessible even to non-experts and applicable for routine industrial process monitoring and materials analysis. Raman chemical imaging has the capability to characterize heterogeneous systems without the need for significant sample preparation. Chemical imaging allows one to visualize the composition and spatial distribution of constituents that dictate material function, which is fundamental to characterizing advanced composite materials. An optimized Raman imaging system based on an LCTF can readily be used to analyze a wide variety of materials, including polymers, corrosion resistant alloys, and pharmaceuticals. In Phase I, we will demonstrate feasibility by constructing a high resolution filter and using it in a microscope to obtain Raman images from test samples. A Raman chemical imaging system will have broad applicability in the polymer and coatings industries for chemically specific visualization of domains and defects without the need for sample staining. In-situ monitoring of corrosion in ferrous alloys is another important use, while a third application lies in quantitative studies of polymorphism in pharmaceutical crystalline materials.
