In some implementations, an optical assembly comprises an optical cavity; one or more detectors; and an optical component having an input face and an output face configured to receive an input beam to the input face and to produce one or more primary output beams, and a plurality of secondary output beams from the output face, the secondary output beams resulting from multiple internal reflections within the optical component. At least one of the input face is not perpendicular to the input beam or the output face is not perpendicular to the one or more primary output beams. Each primary output beam is transmitted through the optical cavity perpendicular to at least one surface of the optical cavity, and directed to a respective one of the one or more detectors. Each detector is arranged to exclude at least a portion of each secondary output beam.

An etalon may include a plurality of reflectors, wherein at least one reflector, of the plurality of reflectors, is partially reflecting of light in a frequency range and each other reflector, of the plurality of reflectors is either partially or fully reflecting of light in the frequency range, and wherein the plurality of reflectors comprises at least three reflectors arranged to define a volume of a resonant optical cavity.

A device for day lighting the interior of structure deploys reflective louvers that are spaced apart in stacks. The louvers include a coating or multilayer structure that is operative to reflect visible light but transmit IR light through the louver. The louvers also have a retro-reflective structure to return the IR light by reverse reflection in the opposite direction of the incident light, which is back toward the sun. The interior of the structure is more uniformly illuminated with visible light while the louvers and interior are not heated by IR light or radiation from the sun.

An optical arrangement converts an input laser beam into a line-like output beam, which propagates along a propagation direction and which has, in a working plane, a line-like beam cross section extending along a line direction. The optical system includes: a reshaping optical unit having an input aperture, through which the input laser beam is radiated, and an elongate output aperture, elongatedly extending along an aperture longitudinal direction, the reshaping optical unit converting the input laser beam radiated through the input aperture into a beam packet exiting through the output aperture; and a homogenization optical unit which converts the beam packet into the line-like output beam, different beam segments of the beam packet being intermixed and superimposed along the line direction. The aperture longitudinal direction extends in a manner rotated about the propagation direction by a non-vanishing angle of rotation with respect to the line direction.

An optical device introduces light from an outdoor view in a blind spot area hidden by an obstacle. The optical device includes a first reflector that reflects a part of light and transmits another part of the light, and a second reflector placed between a back surface of the first reflector and the obstacle and apart from the first reflector. The second reflector has a reflective surface that reflects light incident from the first reflector toward the first reflector. A light shield is placed at a front surface of the first reflector to block external light incident on and reflected from the front surface of the first reflector. The light shield includes light-shielding plates arranged at an interval in a vertical direction such that each light-shielding plate is horizontal. The first reflector is parallel to the reflective surface of the second reflector and tilted from a vertical axis.

A method of fabricating a compound light-guide optical element (LOE) is provided. A bonded stack of a plurality of LOE precursors and a plurality of transparent spacer plates alternating therebetween is bonded to a first optical block having a plurality of mutually parallel obliquely angled internal surfaces. The block is joined to the stack such that first plurality of partially reflective internal surfaces of the block is non-parallel to the internal surfaces of the LOE precursor. After bonding, a second optical is thereby formed. At least one compound LOE is sliced-out of the second optical block by cutting the second block through at least two consecutive spacer plates having a LOE precursor sandwiched therebetween.

A display has an image projector projecting collimated image illumination along a projection direction, and an optical element having two major surfaces and containing partially reflective surfaces which are internal to the optical element, planar, mutually parallel and overlapping relative to the projection direction. Each ray of the collimated image illumination enters the optical element and is partially reflected by at least two of the partially reflective surfaces so as to be redirected to exit the first major surface along a viewing direction. An alternative implementation, a first reflection from one of the partially reflective surfaces redirects part of the image illumination rays so as to undergo total internal reflection at the major surfaces of the optical element. The rays are then redirected by further reflection from another of the partially reflective surfaces to exit the optical element along the viewing direction.

A see-through display including a polarized reflective pinhole mirror display. The pinhole mirror display includes a plurality of tiny switchable polarized mirrors. The respective polarized mirrors individually reflect impinging light from an illuminator, and guide the respective portion of light into a pupil of an eye. A reflective optically powered surface reflects light from the illuminator. Each mirror has a first polarization and reflects a portion of light and produces a picture element (pixel) that forms a virtual image seen by the eye of the user. A user may view the reflected virtual image having the first polarization from the illuminator, as well as the image from the real world via a rear substrate that has a second polarization. Although the mirrors are very small, human eyes can still detect the mirrors if they are not polarized. The mirrors and other components are polarized so that the eye can see the real world filtered with the second polarization, but not the mirrors having a different first polarization.

A light guide includes: a first light guide portion including: an optical entrance; and multiple reflecting surfaces including at least one first reflecting surface and at least one second reflecting surface, the multiple reflecting surfaces configured to separate a light flux entered through the optical entrance, into multiple light fluxes; and a second light guide portion including an optical exit. The second light guide portion is configured to cause the multiple light fluxes to propagate therethrough and exit from the optical exit. A part of the light flux strikes and reflects off the at least one first reflecting surface to propagate into the second light guide portion. Another part of the light flux strikes and reflects off the at least one second reflecting surface without striking the at least first reflecting surface, to propagate into the second light guide portion.

A louver includes a light blocking portion having a first surface and a second surface and a base portion made of a transparent material. The light blocking portion is formed in the base portion, being made of a light blocking material. The second surface is a surface that is in contact with the transparent material and that is located on an outer-edge side of the base portion. The first surface is a surface that is in contact with the transparent material and that is opposite to the second surface. A surface roughness of the first surface is larger than a surface roughness of the second surface.