Narrow wavelength polarizing beamsplitter
US5828489A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Apr 12, 1996 |
| Grant date | Oct 27, 1998 |
| Priority date | — |
| Expiry date | Apr 12, 2016 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG02B27/283
- WIPO fieldOptics
- WIPO sectorInstruments
Abstract
A polarizing beamsplitter includes a gradient index film, such as a rugate filter, embedded in an optical medium. The rugate filter is comprises a thin film having a sinusoidal variation in refractive index through its thickness. The embedding medium may include a pair of prisms with the rugate filter between joining faces of the prisms. The rugate filter is embedded so that an incident beam in the embedding medium forms an angle with respect to a normal from the plane of the rugate filter. Embedded at a non-orthogonal angle, the rugate filter is highly transmissive for both the p- and s-polarized broadband components of the incident beam. The beamsplitter is highly reflective, however, at an s-polarization narrow wavelength reflection band determined by the refractive index variations of the rugate filter. Polarizing beamsplitters may be fabricated with multiple reflection bands, including reflection bands in spectral regions other than the visible spectrum. The polarizing beamsplitter can function as a polarizer, a beamsplitter, or a polarizing beamsplitter. An advantage of the invention is efficient reflection of s-polarized light at specific narrow wavelengths with high transmi…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.