An optical device includes a light source and a polarization selective optical element. The polarization selective optical element includes a stack of a plurality of cholesteric liquid crystal layers. The plurality of cholesteric liquid crystal layers includes a first cholesteric liquid crystal layer with liquid crystal molecules arranged in a first helical configuration having a first pitch range for light of a first wavelength range and a second cholesteric liquid crystal layer with liquid crystal molecules arranged in a second helical configuration having a second pitch range for light of a second wavelength range. The second wavelength range is different from the first wavelength range.

An isolator based on a waveguide-based artificial dielectric medium is scalable to a range of desired terahertz frequencies, has non-reciprocal transmission and provides low insertion loss and high isolation at various tunable terahertz frequencies, far exceeding the performance of other terahertz isolators, and rivaling that of commercial optical isolators based on the Faraday effect. Because terahertz artificial dielectrics are low loss, inexpensive, and easy to fabricate, this approach offers a promising new route for polarization control of free-space terahertz beams in various instrumentation applications. Artificial dielectrics are man-made media that mimic properties of naturally occurring dielectric media, or even manifest properties that cannot generally occur in nature. A simple and effective strategy implements a polarizing-beam-splitter and a quarter wave plate to form a highly effective isolator. Performance of the device is believed to exceed that of any other experimentally demonstrated method for isolation of back-reflections for terahertz beams.

An example apparatus may include a display and an optical configuration configured to provide an image of a display, for example, in a head-mounted device. The optical configuration may include a Fresnel lens assembly including a Fresnel lens and a reflective polarizer. The Fresnel lens may have a structured surface including a plurality of facets, and there may be a step between pairs of neighboring facets. The reflective polarizer may include a plurality of reflective polarizer portions, where each reflective polarizer portion conforms to a corresponding facet of the Fresnel lens. The reflective polarizer may be configured to reflect a first polarization and transmit a second polarization of incident light. The optical configuration may form an image of the display viewable by a user when the user wears the apparatus. Other devices, methods, systems, and computer-readable media are also disclosed.

A system includes a source configured to emit partially spatially coherent light and a metasurface located proximate to a light emitting surface of the source, where the metasurface is configured to modify at least one property of the emitted light. Modifiable properties include phase, amplitude, directionality, far field profile, and polarization. The metasurface may be passive or active. An active metasurface may be controlled using an input such as applied voltage, temperature, and mechanical force. The system may be configured to provide coherent illumination.

A wire grid polarizer (WGP) can include an array of support-ribs on a substrate. Sides of the support-ribs can be inclined to one side. A wire can be applied on an upper-side and distal end of each support-rib, each wire being separate from wires on adjacent support-ribs. The WGP can be made with reduced or no etching.

The present disclosure is directed to a method of forming a polarization grating structure (e.g., polarizer) as part of a grid structure of a back side illuminated image sensor device. For example, the method includes forming a layer stack over a semiconductor layer with radiation-sensing regions. Further, the method includes forming grating elements of one or more polarization grating structures within a grid structure, where forming the grating elements includes (i) etching the layer stack to form the grid structure and (ii) etching the layer stack to form grating elements oriented to a polarization angle.

The optical device comprises a group of Fabry-Perot resonators, formed by a stack of a first and second partial reflection layer and an intermediate layer between the first and second partial reflection layer. The intermediate layer comprises a dielectric material and a group of arrays of posts embedded in the dielectric material at different positions along the intermediate layer. Each array in the group contains posts of a different non-circular shape and/or orientation in cross-section with a plane parallel to the reflection layers. As a result, Fabry-Perot resonators are formed in areas that contain different arrays, each having first and second resonance peaks at mutually different resonance frequencies for different polarization components. Light intensity sensors may be provided located below the different areas. From the intensities measured by the sensors, the intensities of different polarization components of the light can be computed over a range of wavelengths.

Provided are a polarizing plate having excellent optical properties and durability, and a method for manufacturing the polarizing plate. The polarizing plate includes: a transparent substrate transparent to light in a used wavelength band; lattice-shaped protrusions arranged on the transparent substrate at a pitch shorter than the wavelength of light in the used wavelength band, extending in a predetermined direction, and having a reflective layer, a first dielectric layer, an absorbing layer, and a second dielectric layer in this order; a dielectric portion consisting of a dielectric discontinuously formed on a surface of the lattice-shaped protrusions and a surface of a bottom floor between the lattice-shaped protrusions; and a water-repellent portion formed on a surface of the dielectric portion and having water-repellent properties.

A wire grid polarizer (WGP) can include an array of support-ribs on a substrate. Sides of the support-ribs can be inclined to one side. A wire can be applied on an upper-side and distal end of each support-rib, each wire being separate from wires on adjacent support-ribs. The WGP can be made with reduced or no etching.

The present disclosure is directed to a method of forming a polarization grating structure (e.g., polarizer) as part of a grid structure of a back side illuminated image sensor device. For example, the method includes forming a layer stack over a semiconductor layer with radiation-sensing regions. Further, the method includes forming grating elements of one or more polarization grating structures within a grid structure, where forming the grating elements includes (i) etching the layer stack to form the grid structure and (ii) etching the layer stack to form grating elements oriented to a polarization angle.