High-efficiency cosine-approximated binary Gabor zone plate.

A cosine-approximated binary Gabor zone plate is proposed. The zone plate is fabricated by standard photographic techniques. It was evaluated by simulation and by experiment to match the focusing behavior of an ideal Gabor zone plate, but it has a focusing efficiency at least 23% higher than that of a binary Gabor zone plate. Duplication of an alphabetic character to form a 4 × 4 array of images with little astigmatism by the proposed zone-plate array is demonstrated.