• Optical beamscanner reduces laser wobble

    Optical scanners intended to modulate or deflect light are often galvanometer-based mechanical systems.
    July 1, 2011
    2 min read

    Optical scanners intended to modulate or deflect light are often galvanometer-based mechanical systems. At high materials-processing speeds, demands on the bearings for moving parts are exceptionally high, and cross-axes wobble (the vertical deviation of a scanned laser beam from its nominal linear axis) is typically on the order of 200 μrad. But a new silicon-based resonant microelectromechanical systems (MEMS) scanner from the Fraunhofer Institute for Photonic Microsystems (IPMS; Dresden, Germany) has demonstrated cross-axes wobble less than 35 μrad; the scanner oscillates at 23 kHz with a mechanical amplitude of ±9°.

    A typical Fraunhofer MEMS scanner chip (4.0 × 2.6 mm2) deflects a beam using an aluminum-coated (reflectivity greater than 86% between 450 to 650 nm), 1.2-mm-diameter, circular silicon MEMS mirror. With average power consumption lower than 300 µW, the scanner operates at laser powers up to 600 mW at 670 nm. Unlike galvanometer-based scanners, the design uses photolithographic methods to enable high symmetry and reduce unbalanced masses. And, compared to other MEMS designs, the actuation—based on interdigitated-comb structures—creates a very energy-efficient driving mechanism and minimizes process-related accidental asymmetry. More than 150 MEMS scanner designs can be accessed online using the Fraunhofer IPMS Scanner-Configurator. The customer simply inputs the desired scan frequency, maximum mechanical amplitude, mirror diameter, and maximum mechanical deformation that can be tolerated.

    Contact André Dreyhaupt at [email protected].

    About the Author

    John Wallace

    Senior Technical Editor (1998-2022)

    John Wallace was with Laser Focus World for nearly 25 years, retiring in late June 2022. He obtained a bachelor's degree in mechanical engineering and physics at Rutgers University and a master's in optical engineering at the University of Rochester. Before becoming an editor, John worked as an engineer at RCA, Exxon, Eastman Kodak, and GCA Corporation.

    Sign up for Laser Focus World Newsletters
    Get the latest news and updates.

    Voice Your Opinion!

    To join the conversation, and become an exclusive member of Laser Focus World, create an account today!