A novel type of liquid microlens, bounded by a microfabricated, distensible membrane and activated by a microfluidic liquid-handling system, is presented. By use of an elastomer membrane fabricated by spin coating onto a dry-etched silicon substrate, the liquid-filled cavity acts as a lens whereby applied pressure changes the membrane distension and thus the focal length. Both plano-convex and plano-concave lenses, individual elements as well as arrays, were fabricated and tested. The lens surface roughness was seen to be ∼9 nm rms, and the focal length could be tuned from 1 to 18 mm. This lens represents a robust, self-contained tunable optical structure suitable for use in, for example, a medical environment.
© 2005 Optical Society of America
(010.1080) Atmospheric and oceanic optics : Active or adaptive optics
(220.3620) Optical design and fabrication : Lens system design
(220.3630) Optical design and fabrication : Lenses
(350.3950) Other areas of optics : Micro-optics
Armin Werber and Hans Zappe, "Tunable microfluidic microlenses," Appl. Opt. 44, 3238-3245 (2005)