1985-05-23
1987-05-05
Punter, William H.
350164, G02F 121, G02B 110
Patent
active
046627227
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.
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Buczek Carl J.
Myers James G.
Ford Aerospace & Communications Corp.
Punter William H.
Radlo Edward J.
Zerschling Keith L.
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