An optical system for displaying a magnified virtual image of an image emitted by a display to a viewer. The optical system includes first and second lenses facing each other and spaced apart by an air gap to define an optical cavity therebetween. The optical cavity includes a reflective polarizer disposed on a major surface of the first lens, and an optical stack disposed on a major surface of the second lens. The optical stack includes an absorbing polarizer, a first retarder layer, a partial reflector, and a second retarder layer disposed between the absorbing polarizer and the partial reflector. The first and/or second lenses is/are birefringent lens provided outside the optical cavity to control polarization.

A laser crystallization apparatus according to an embodiment includes: a light source unit which irradiates a laser beam; and a path conversion unit which converts the laser beam incident from the light source unit into a linear beam having a long axis parallel to a first direction and a short axis parallel to a second direction. The linear beam propagates in a third direction perpendicular to the first direction and the second direction, the path conversion unit includes an incident window extending parallel to a first length direction, an emission window extending parallel to a second direction, a first reflection unit disposed at the same side with the incident window, and a second reflection unit disposed at the same side with the emission window, and the second length direction extends parallel to the first direction in a view of the third direction.

Detecting systems configured to detect airborne viruses, and methods of forming the same, are provide. A method for preparing a system for detecting an airborne virus includes preparing a thin-film coating on a surface of a substrate; ablating the coating to form an optical grating structure; and associating a plurality of receptors having an affinity and specificity for the virus with the optical grating structure so that the structure is capable of indicating the presence of the virus. A detecting system includes the optical grating structure and an optical component. The optical component includes a cavity defined by two opposing reflecting surfaces and configured to receive the optical grating structure, and a light source disposed adjacent to an exterior surface of a first reflecting surface. The light source may be configured to direct light towards the first reflecting surface so that light in resonance enters the cavity.

A multiple-reflection apparatus and a multiple-reflection cell includes: a pair of parallel plane mirrors that multiply reflects a laser light, in zigzag, which enters at a specific angle of incidence; a right-angle double mirror having two perpendicular reflection surfaces for returning the multiple-reflection light that traveled to one end between the parallel plane mirrors; and a right-angle double mirror having two perpendicular reflection surfaces for returning the multiple-reflection light that traveled from the right-angle double mirror on one end side to the other end between the parallel plane mirrors. When the two parallel mirror surfaces configuring the parallel plane mirrors are disposed to be parallel to the z-x plane of the x-y-z axial coordinate system, the two reflection surfaces configuring the right-angle double mirror are perpendicular to the x-y plane, and the laser light entering at the angle φ of incidence crosses the x-y plane at a specific angle [[φz]].

An optical device for a head-mounted display device includes a first partial reflector and a second partial reflector positioned relative to the first partial reflector so that the second partial reflector receives first light transmitted through the first partial reflector and reflects at least a portion of the first light toward the first partial reflector as second light. At least a portion of the second light is reflected by the first partial reflector as third light, and at least a portion of the third light is transmitted through the second partial reflector. At least one of the first partial reflector or the second partial reflector includes a reflective holographic element.

Systems and methods for manipulation of the polarization state of light emitted by a laser projector to reduce the angle range of a scanning mirror articulated by a micro-electromechanical system MEMS to reduce power consumption are disclosed. A system includes a light source configured to emit laser light, a scanning mirror, and an angle expander disposed between the light source and the scanning mirror, the angle expander being configured to cause the laser light from the light source to be reflected at least once from the angle expander and at least twice from the scanning mirror.

Method and apparatus to maintain a resonant condition of an optical cavity such that the optical path length through the optical cavity is independent or minimally dependent on the angle of incidence of a received optical signal are disclosed. A material within the optical cavity has an index of refraction that varies as a function of an angle of propagation of light within the material, thereby achieving the independence of the optical path length and the angle of incidence. The resonant condition is maintained over a range of angles of incidence of the received optical signal.

A passive cooler of the disclosure includes a thermal emitter having a substrate and a coating disposed on at least a portion of a first side of the substrate. The cooler has a beam guide made from a material having a high absorption to solar wavelengths and high reflectance at mid-infrared wavelengths. The beam guide is configured such that at least a portion of incident light is acted on by the beam guide before reaching the thermal emitter. In some embodiments, the beam guide has a graded optical index.

Described are two mirror scanning projectors employing a collimated laser beam directed to a first mirror that scans in one direction, an optical relay system, and a second mirror that scans in a perpendicular direction from the first mirror to provide two dimensional scanning of the laser beam.

An optical device for a head-mounted display device includes a first partial reflector and a second partial reflector positioned relative to the first partial reflector so that the second partial reflector receives first light transmitted through the first partial reflector and reflects at least a portion of the first light toward the first partial reflector as second light. At least a portion of the second light is reflected by the first partial reflector as third light, and at least a portion of the third light is transmitted through the second partial reflector. At least one of the first partial reflector or the second partial reflector includes a reflective holographic element.