Optimization of Coarse Approach for an Atomic Force Microscope (AFM) Design

Coarse approach for an AFM accomplishes the challenging task of moving a probe several millimeters with nanometer precision. We designed a coarse approach mechanism using the koala drive design with three sapphire disks clamped to the probe by molybdenum springs, each separately moved by a piezoelectric tube. Each disk should slip when moved, but stick when another leg is moved. Procedures for measuring when disks were sticking and slipping using interferometry were developed. The results have shown us that motion is improved using four points of contact instead of our original six points of contact. Interferometry also allows us to make informed adjustments to the spring clamping strength to improve motion.