Ultra-sparse dielectric resonant polarizers and associated methods
View Patent ↗The invention disclosed herein generally relates to wideband resonant polarizers that require extremely small amounts of matter in their embodiments. These polarizers can be made with dielectric materials such that light and other electromagnetic waves interacting with them suffer essentially no absorptive loss. This new class of polarizers is fashioned with dielectric or semiconductor nano/microwire grids that are mostly empty space if surrounded by air or vacuum. It is fundamentally and practically extremely significant that the wideband spectral expressions presented herein can be generated in these minimal systems. These ultra-sparse polarizers are useful in various spectral regions for numerous useful applications.
1. A sparse grating polarizer comprising:
a grating layer composed of a material with a dielectric constant of ε 1 ; and
a host region with a dielectric constant of ε 0 ;
wherein said grating layer is present in the polarizer and is embedded in said host region;
wherein said grating layer has a fill factor F that is less than 0.3;
wherein the dielectric constant ε 1 lies in the range of 2 to 1000;
wherein the dielectric constant ε 0 lies in the range of 1 to 100;
wherein said polarizer, when illuminated by any incident electromagnetic wave within a spectral band, causes reflection of a TE-polarized electric-field component of the incident electromagnetic wave within the spectral band and transmission of a TM-polarized electric-field component of the incident electromagnetic wave within the same spectral band;
wherein the TM-polarized electric-field component is neither diffracted nor guided by the polarizer within the spectral band;
wherein the TE-polarized electric-field component is both diffracted and guided by the polarizer within the spectral band;
wherein TE-polarized reflectance of the incident electromagnetic wave exceeds 90% within the spectral band;
wherein TM-polarized transmittance of the incident electromagnetic wave exceeds 90% within the spectral band; and
wherein the spectral band is within a spectral region selected from the group of ultra-violet, visible, infrared, near-infrared, THz, and microwave regions.
2. The polarizer in claim 1 , wherein:
the grating layer is made from a material selected from the group of Si, Ge, GaAs, GaP, SiC, TiO 2 , HfO 2 , SiO 2 , and GaN; and
the host region is selected from the group of air, vacuum, polymer, plastic, glass, spin-on glass, oil, liquid crystal, silicone, polydimethylsiloxane and water.
3. The polarizer in claim 1 , where the grating layer is made from a material selected from the group of Si, Ge, GaAs, GaP, SiC, TiO 2 , HfO 2 , SiO 2 , and GaN.
4. The polarizer in claim 1 , where the host region is selected from the group of air, vacuum, polymer, plastic, glass, spin-on glass, oil, liquid crystal, silicone, polydimethylsiloxane and water.
5. The polarizer in claim 1 , where the incident electromagnetic wave has a polarization state selected from the group of randomly polarized, unpolarized, linearly polarized, elliptically polarized, and circularly polarized.
6. The polarizer in claim 1 , where the incident electromagnetic wave is at normal incidence.
7. The polarizer in claim 1 , where the incident electromagnetic wave is at non-normal incidence.
8. The polarizer in claim 1 , wherein said grating layer has a fill factor F of 0.05 to 0.12.