Hybrid Optical Elements for Spot Array Generation and Focusing.

Binary phase gratings are a form of computer generated holograms that allow the generation of desired spot array patterns at their far field output. When used in an optical system, a focusing lens at the output of the grating converts an incident plane wave into a spot array pattern at the focal play of the lens. The digitization of the lens allows the grating and the lens to be combined onto a single substrate to minimize the number of elements required in the system. It also permits consistent control of optical aberrations. The performance of digital lenses is studied, and these results used to design a hybrid element that combines the lens and grating onto a single substrate. The characteristics and performance of the hybrid device are presented and its limitations discussed.