Polarization insensitive multilayer planar reflection filters with near ideal spectral response
US5777793A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jul 25, 1996 |
| Grant date | Jul 7, 1998 |
| Priority date | — |
| Expiry date | Jul 25, 2016 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG02B2006/12164
- WIPO fieldOptics
- WIPO sectorInstruments
Abstract
A polarization insensitive, multilayer planar reflection filter is provided having (I) strong sidelobe suppression, preferably with sidelobe suppression levels in the range of -30 dB to -50 dB, and (ii) minimum width of the filtered bandwidth for the specified sidelobe suppression level. The multilayer planar reflection filter is provided by a multilayer stack by specifying the manner in which the thickness of the individual dielectric layers are to be varied throughout the stack. The resulting universal design formula specifies these layer values for a stack with an arbitrary number of layers, dielectric constant, incident angle, and wavelength. In particular, the layer thickness values of the alternating layer d.sub.1 (j) in refractive index n.sub.0, and d.sub.2 (j) in refractive index n.sub.0 +.DELTA.n, vary with each period j and are determined to provide a specified central wavelength, sidelobe suppression and minimum filtered band width. The filter is polarization insensitive because the period required for maximum reflection at wavelength .lambda..sub.0 is the same for both TE and TM polarized light.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.