Multiorder diffractive lenses with low f-number

Abstract

Recent liquid crystal on silicon (LCoS) spatial light modulators (SLMs) working on reflection can achieve large phase modulation ranges, permiting the implementation of multiorder diffractive lenses. These lenses are designed so that they have q2p phase modulation jumps between adjacent facets, being q a positive integer. Such diffractive optical elements (DOEs) overcome the aliasing effects that usually appear on conventional modulo 2p diffractive lenses with low f-number. Details on the boundaries of these lenses vary very rapidly and can be limited by the Nyquist resolution limit when they are displayed on pixelated structures. We present experimental results that show the improvement of focusing a collimated beam at a short distance by using a multiorder diffractive lens in comparison with a conventional first-order diffractive lens. A prior calibrating procedure is carried out to optimize the LCoS SLM performance when multiorder lenses are displayed on the modulator.