Magnetically actuated scanning microlens for NIR Raman spectroscopy

This paper presents the design, fabrication and characterization of a magnetically actuated scanning microlens for miniature confocal near infrared (NIR) Raman spectroscopy. One of the potential applications could be on non-invasive skin cancer diagnosis. The microlens is comprised of a 20 mum thick ferromagnetic nickel platform integrated with a PDMS plano-convex lens with a diameter of 1.25 mm and an effective focal length of 2.0 mm. This work demonstrates a microlens with a scanning angle of plusmn24deg driven by an external AC magnetic field orientated at an angle of 30deg from the horizontal rotation axis. A coplanar 152 mum scanning range is demonstrated by a 22.2times10^-3 Tesla external magnetic field at 197 Hz.