Abstract

A variety of applications exist for a compact, wide field-of-regard optical system that allows beam steering and serves as an optical window and the system aperture stop. Recently, a study was performed to investigate the possibility of designing and fabricating a small array of miniature lenses that would allow a detector array with an instantaneous field of view of 1.5° to be swept through an angle of up to 60° by simple movement of an element in the optical system. It was found that such designs with essentially diffraction-limited performance can be formulated for the 3.1–4.1 µm spectrum by using afocal modules comprising only two silicon lenses, where the second lens moves with respect to the first lens to provide the beam steering action. The spatial path followed by the second lens can be made to be circular with almost no degradation in performance, thereby minimizing the complexity of the scan mechanism. Results are presented that demonstrate the robust nature of the beam steering optics to large thermal gradients. Specific designs for one-dimensional and two-dimensional scanning systems with multiple lens modules are be discussed.

© 1992 Optical Society of America