Liquid-crystal active lens: a reconfigurable lens employing a phase modulator

Abstract

The proposed active lens consists of a lens attached to a liquid-crystal two-dimensional phase modulator and it provides both a variable focal length and image processing capability. Since the lens has main refractive power and the phase modulator provides a small and variable power, the device features a large and variable power and a small F number. It can also perform convolution-based image processing in an incoherent imaging system, since its intensity point-spread function can be controlled by changing the modulator's phase distribution. A prototype device varied its focal length from 0.23 m to 0.28 m and image-shifting, image-splitting and matched-filtering operations were experimentally demonstrated.