*** 9760231 Krishnan This Small Business Innovation Research Phase I project will explore how the change in polarization state for light reflected by a surface might be employed as a tool for quantitative surface roughness, crack, and defect detection. The approach is enabled by recent advances in four-detector polarimetry that provide high measurement rates, non-invasive measurement, and sensitivity to roughness, crack, and defect dimensions of 0.1(m or less. The use of physical optics effects facilitates operation in production facilities with minimal mechanical and thermal control requirements. The approach offers (i) simultaneous measurement of intrinsic (e.g., chemical composition) and extrinsic properties (roughness, crack and defect concentrations, presence of overlayers), via Mueller matrix ellipsometry (MME), and (ii) fast single point scanning of surfaces to map defects. The Phase I effort will (i) expand the scientific database for MME on rough surfaces and correlation of measurements with surface properties, (ii) evaluate detection of defects less than 0.1 (m to several microns, (iii) determine viability of polarization measurements for surface inspection of jet engine turbine blades, and (iv) develop design and software/modeling approaches for automated on-line process monitoring and NDE. Successful completion of the Phase I research would lead, in Phase II, to the demonstration of a prototype instrument for advanced non-invasive measurements in surface science, tribology, for quality control in manufacturing operations, and in the NDE of materials and structures. ***
