The objective of the materials part of this research program is to investigate complex light-matter interactions in sapphire to facilitate the design, fabrication and testing of high temperature sensors that can operate up to -l400oC in chemically corrosive environments. Sapphire has ideal chemically resistant and high melting point material properties critical for developing sensors that can operate in hostile environments; however, material machinability is challenging in comparison to standard MEMS silicon etching methods. We propose to overcome this challenge using laser machining techniques. Our goal is to create high strength sapphire structures to significantly improve the sensor performance. We plan to achieve this by investigating fundamental light-matter interactions and damage evolution in sapphire (experimental characterization, modeling, and uncertainty quantification) in combination with practical design and characterization of a sensor capable of high temperature operation. Hypothesis: Increasing laser power applied to sapphire leads to a transition from dislocations and metastable phase formation to microcracking. After irradiation, high temperature thermal annealing (800oC to 1200"C) will partially reverse the surface damage. Both of these effects have important implications on fracture and brittle-to-ductile transitions at higher temperature. Understanding the underlying mechanisms associated with micro and nanostructure evolution during laser machining and postmachined thermal annealing is critical to the development of a robust sensor design capable of long term operation in hostile environments.