Abstract: A polarization insensitive mirror (3) comprises a single homogeneous coating (1) coated onto a typically metallic reflective surface (2). The mirror (3) is substantially insensitive to polarization of incident radiation (4) over a wide range of angles of incidence (A). The coating (1) has an index of refraction (n) greater than 2.4, is substantially transmissive to the incident radiation (4), and has a thickness (t) substantially equal to L.sub.0 /2n, where L.sub.0 is the wavelength of the incident radiation (4) in freespace. Germanium makes a good coating (1). The reflective surface (2) is typically gold or silver. Increasing slightly the thickness (t) of the coating (1) increases the range of incident angles (A) over which the mirror (3) exhibits minimized phase differentials (B). Graphs (FIGS. 3-8) are presented comparing the reflectivity, phase differential (B), and average reflectivity of mirrors (3) fabricated according to the teachings of the present invention with those of the prior art.

Abstract: In a system employing a collimated beam projector radiating energy of a single wavelength and an image detector sensitive to a band of wavelengths, a boresight technique includes the steps of extracting a portion of the projected beam, focusing the extracted portion onto a predetermined point of a boresight target material until said material responsively emits radiation in said band of wavelengths, and collimating the emitted radiation into said image detector at a field of view location corresponding to the projected beam location.