THE OPTIMIZATION OF DIFFRACTIVE BINARY MIRRORS WITH LOW FOCAL LENGTH DIAMETER RATIOS/

Lenses in transmission or mirrors in reflection with a low ratio of fo cal length td diameter represent a problem in diffractive optics due t o the high spatial frequencies involved. In this paper rigorous diffra ction theory is used to calculate and to optimize focusing diffractive mirror arrays with a binary structure. Also metallic artificial diele ctrics, which consist of binary sub-wavelength structures, are optimiz ed. The initial design for the elements is carried out using approxima te theory. The performance of the elements is evaluated using the crit eria diffraction efficiency and wavefront quality.