Polarization insensitive mirror
US4662722A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | May 23, 1985 |
| Grant date | May 5, 1987 |
| Priority date | — |
| Expiry date | May 23, 2005 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG02B5/0858
- WIPO fieldOptics
- WIPO sectorInstruments
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.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.