Fast focus-shifter based on a unimorph deformable mirror

摘要

On-the-fly remote laser processing plays an increasingly important role in modern fabrication techniques. These processes require guiding of the focus of a laser beam along the contours of the workpiece in three dimensions. State-of-the-art galvanometer scanners already provide highly dynamic and precise transverse x - y beam steering. However, longitudinal focus shifting ("z-shifting") relying on conventional optics is restricted to a bandwidth of a few hundred Hz. We have developed and manufactured a fast piezo-based z-shifting mirror with diffraction-limited surface fidelity providing a focus shift of Delta z > 60mm with an actuation rate of 2 kHz. (C) 2020 Optical Society of America.