Fabrication of microfluidic hemicylindrical lenses for light scanning of laser sheet

A light scanning device with two microfluidic hemicylindrical lenses was demonstrated for adjustable laser sheet beam scanning applications. An elastomeric hemicylindrical lens, whose focal length can be adjusted by control of the applied fluidic pressure, was fabricated by application of the pressurized casting process on polydimethylsiloxane (PDMS) obtained from a prepared microsized mold. The hemicylindrical lens consisted of a thin membrane, a liquid chamber and a microchannel. The applied fluidic pressure deformed the lens membrane and changed the lens shape. The change of the lens shape allowed beam shape transformation or beam scanning according to the relative size of the beam to the lens. By orthogonally placing two microfluidic lenses of different sizes, 1 mm × 5 mm and 3 mm × 15 mm, respectively, a spot laser beam from a 200μm-large pinhole was transformed into laser sheet, and then the laser sheet was scanned. The relationship between the lens properties, including lens curvature and laser beam shaping according to different applied pressures on the lens, were systematically investigated. Laser beam scanning properties of the microfluidic light scanning device were also characterized for various applied pressures and offset distances.