Performance trade-offs for conventional lenses for free-space digital optics.

We describe the limitations on the use of conventional lenses in optical computing that arise from manufacturing tolerances. The consequences on maximum array size, minimum device size, and propagation delay of systems are discussed. Two experimental optical computing systems are then compared with these results. We show that there are maximum and minimum bounds on the focal length and the ƒ-number of lenses imposed when manufacturing tolerances are considered. We also show that there are maximum bounds on image sizes and space-bandwidth products and trade-offs between spot size and system latency.