Projects

Achromatic lenses are corrected for chromatic aberrations, and are classically fabricated using two glasses with differing dispersion. We are developing here a liquid-based tunable micro-lens, with variable focal length, based on membrane-defined micro-fluidic cavities. Through the use of appropriate optical liquids, achromaticity is maintained throughout the tuning range. The lens is based on multiple polymer micro-fluidic cavities bounded by flexible PDMS membranes; the structure, as shown in the figure, is reminiscent of the classical cemented Fraunhofer doublet. By applying pressure to the cavities, the membranes deform, thereby tuning the focal length. The liquids are chosen so that the dispersion is compensated and the lens remains achromatic throughout the tuning range.