Laser Micromachining of Optical Structures and Surfaces

Advanced laser micromachining technology will prove to be a vital fabrication tool for high precision devices having functional features on the mesoscopic and microscopic scale. The proposed program will establish the fundamentals of advanced 3-D high precision laser micromachining of SiC and Si3N4 devices. The approach utilizes next generation high pulse repetition rate solid-state laser systems having pulse durations in the nanosecond, picosecond, and femtoseconds regimens. The laser-material interaction is an extremely dynamical process and changes imposed on the material may include morphological defects, oxidation, chemical decomposition, nano/micro cracking, and compressive or tensile stresses. The dependence of these effects on the laser processing parameters will be quantified using various high-resolution micro non-destructive evaluation (micro-NDE) techniques employing advanced sensor technology (AST). Micro-NDE will be utilized to define the optimal processing window for laser micromachining SiC and Si3N4. AST techniques such as laser-ultrasonics and thermal wave imaging will be used as a process monitoring and a quality assurance technique. Additionally, AST process monitoring will be evaluated as a possible process control technology.