Two optical designs for infrared imagers, a fast (F/1) staring system and a slower (F/2.4) scanning system, are discussed to demonstrate the advantages and limitations of using hybrid diffractive/refractive elements as replacements for conventional elements. Each case is compared to a conventional design of all spherical elements satisfying a specific set of hypothetical requirements for resolution, field-of-view, and spectral bandwidth (8-12 μm). We find that as much as a 33 percent reduction in the number of elements can be achieved in the slower system using hybrid elements. For the fast system, spherochromatism greatly limits the performance of the hybrid design. A table is presented showing the trades among F-number, field-of-view, bandwidth, and materials needed to maintain constant resolution in the fast system.

Date Published: 6 May 1989
PDF: 7 pages
Proc. SPIE 1052, Holographic Optics: Optically and Computer Generated, (6 May 1989);

Published in SPIE Proceedings Vol. 1052:
Holographic Optics: Optically and Computer Generated
Ivan Cindrich; Sing H. Lee, Editor(s)