A multimode optical waveguide network comprises a parent waveguide and a plurality of child waveguides. Each waveguide is a multimode optical waveguide having a first surface region, multiple second surface regions, and at least one guiding element attached to a surface of the waveguide or embedded within the waveguide, each second surface region of the parent waveguide optically coupled to the first surface region of a corresponding child waveguide. The guiding element(s) of the parent waveguide is arranged to guide a beam, from or to its first surface region, to or from any selected second surface region of its multiple second surface regions. The guiding element(s) of each of the waveguides is configurable for selecting the second surface region of that waveguide and/or responsive to at least one beam characteristic for selecting the second surface region of that waveguide via modulation of the at least one beam characteristic.

An optical system of the disclosure includes: a fluorescent unit that includes a phosphor region excited by a first color light beam to output fluorescent light including at least one color light beam, and outputs the first color light beam in a first period and outputs the fluorescent light in a second period; one or two light valves illuminated by at least one of the first color light beam or the fluorescent light; and a region division element including first and second regions and disposed on an optical path between the fluorescent unit and the one or two light valves, the first region outputting the first color light beam and the fluorescent light from the fluorescent unit to be able to reach the one or two light valves, the second region outputting the fluorescent light from the fluorescent unit to be able to reach the one or two light valves.

An optical filter includes a first layer including a first notch filter arranged to attenuate electromagnetic radiation having a first wavelength λ.sub.1 incident normally thereupon. The optical filter includes a second layer including a second notch filter arranged to attenuate electromagnetic radiation having a second wavelength λ.sub.2 incident normally thereupon. The first wavelength λ.sub.1 and the second wavelength λ.sub.2 are different. The second layer is stacked upon the first layer. In use, the first notch filter attenuates the electromagnetic radiation having a predetermined wavelength λ incident thereupon at a first angle of incidence θ.sub.1 and the second notch filter attenuates the electromagnetic radiation having the predetermined wavelength λ incident thereupon at a second angle of incidence θ.sub.2, wherein the first angle of incidence θ.sub.1 and the second angle of incidence θ.sub.2 are different.

An integrated computing element for an optical computing device includes a flexible optical substrate. The integrated computing element also includes at least one optical thin film deposited on a first surface of the flexible optical substrate. The at least one optical thin film is configured to selectively pass fractions of electromagnetic radiation at different wavelengths.

A non-imaging concentrator is employed in an upside down configuration in which light enters a smaller aperture and exits a larger aperture. The input angle of light rays may be as large as 180 degrees, while the maximum exit angle is limited to the acceptance angle of the non-imaging concentrator. A dichroic filter placed at the larger aperture has a maximum angle of incidence equal to the acceptance angle of the non-imaging concentrator.

A semi-finished product method with a liquid crystal security feature includes unrolling and transporting a continuous film in a transporting direction and providing on the film a liquid crystal layer containing a substance whose absorption of polarized light depends on its orientation. The method includes at least one of (A) arranging a lacquer layer on the film and embossing it for a first alignment structure, and at least partly covering it with the liquid crystal layer, the first alignment structure able to cause liquid crystal molecules of the liquid crystal layer to align only in a first direction in first regions and only in a second direction, in second regions, and (B) embossing the liquid crystal layer while the liquid crystal layer is uncured providing a second alignment structure to cause liquid crystal molecules to align only in a third direction in third regions and only in a fourth direction, in fourth regions.

An optical filter including: a substrate; and a dielectric multilayer film laid on or above at least one major surface of the substrate as an outermost layer, in which: the dielectric multilayer film is a laminate including a low refractive index film and a plurality of high refractive index films laid on each other; the dielectric multilayer film comprises four or more high refractive index films that are 15 nm or smaller in thickness; the high refractive index films have a minimum thickness of 1.5 to 5 nm; the high refractive index films have a minimum thickness of 100 nm or smaller; the high refractive index films satisfy the following spectral characteristics (i-1) and (i-2); and the optical filter satisfies all of the following spectral characteristics (ii-1) to (ii-4).

A wavelength conversion module includes a base, a wavelength conversion member consisting of a phosphor, and a bonding member including a metal part that bonds the base and the wavelength conversion member. A thickness of the wavelength conversion member is less than 100 μm.

A light detection device includes a Fabry-Perot interference filter, a light detector, a spacer that has a placement surface on which a portion outside a light transmission region in a bottom surface of the interference filter is placed, and an adhesive member that adheres the interference filter and the spacer to each other. Elastic modulus of the adhesive member is smaller than elastic modulus of the spacer. At least a part of a lateral surface of the interference filter is located on the placement surface such that a part of the placement surface of the spacer is disposed outside the lateral surface. The adhesive member is disposed in a corner portion formed by the lateral surface of the interference filter and the part of the placement surface of the spacer and contacts each of the lateral surface and the part of the placement surface.

The present disclosure relates to a decoration member comprising a color developing layer comprising a light reflective layer and a light absorbing layer provided on the light reflective layer; and a substrate provided on one surface of the color developing layer, wherein the light absorbing layer comprises a molybdenum-titanium oxide (Mo.sub.aTi.sub.bO.sub.x).