A 2D circular-scanning piezoelectric MEMS mirror for laser material processing
In this work, 2D piezoelectrically driven MEMS circular scanners have been designed, fabricated and tested. These mirrors own large optical apertures of 7 mm, 10 mm and 20 mm for good beam shapes. Also HR-coating layers for 515 nm and 1050 nm reaching up to 99.99% reflexion and 0.1% transmission were applied onto the mirror surface for the suitability of high power laser, where the wavelengths were specified according to the laser source development demands. Based on piezoelectric position sensing elements integrated on the MEMS mirrors a closed-loop control was developed. In this paper the design efforts, realizing circular-scanning and eliminating non-linearity during mode superposition, and fabrication efforts will be reported. Characterization results focusing on mechanical behaviors, position sensing signal, HR-coating will be also important parts of this work.