An optical pickup device includes a semiconductor laser that emits a laser beam, and an object lens that concentrates the laser beam emitted from the semiconductor laser on an optical disc. In this optical pickup device, an optical axis of the object lens is inclined with respect to an optical axis of the laser beam that is incident on the object lens so as to generate flares caused by coma aberration on an entrance side in a forward direction of pits of the optical disc.

There are provided: a plurality of optical elements for handling light having different wavelengths; a plurality of collimating lenses individually provided in the optical elements, each of the collimating lenses having a first end facing a main surface of one of the optical elements; an optical multi-demultiplexer using reflection of light caused by a spatial optical system, the optical multi-demultiplexer having a first end facing a second end of each of the collimating lenses; a coupling lens having a first end facing a second end of the optical multi-demultiplexer; an SMF having one end facing a second end of the coupling lens; and an optical block, which is transparent, provided on an optical path between each of the collimating lenses and the optical multi-demultiplexer, the optical path having a small number of reflections in the optical multi-demultiplexer.

An illumination optical system includes: a beam splitter located near a conjugate position of a specimen and configured to split beams from a light source into a plurality of groups of beams having different splitting directions around an optical axis; a beam selector configured to select and transmit one group of beams from the plurality of groups of beams and that is rotatable with respect to the optical axis; and a ½ wavelength plate located near the beam selector and rotatable about the optical axis. The rotation angles of the ½ wavelength plate and of the beam selector about the optical axis are respectively set so that the polarization direction of the beam which has passed through the ½ wavelength plate is perpendicular to the splitting direction of the one group of beams that has been selected by the beam selector and split by the beam splitter.

In various embodiments, a beam-parameter adjustment system and focusing system alters a spatial power distribution of a plurality of radiation beams before the beams are coupled into an optical fiber.

An optical element includes a first condensing lens and a plurality of second condensing lenses. The optical element is disposed so as to face an end of an optical fiber. The optical fiber includes a core, a first cladding located around the core, and a second cladding located around the first cladding. The first condensing lens is disposed at a position corresponding to the core. The second condensing lenses are disposed around the first condensing lens at positions corresponding to the first cladding.

In various embodiments, a beam-parameter adjustment system and focusing system alters a spatial power distribution of a plurality of radiation beams before the beams are coupled into an optical fiber.

A screen includes a transparent base body with a front face and a rear face, and an image sensor. The base body includes a coupling-in region and a coupling-out region at a distance therefrom in a first direction. The coupling-in region includes a diffractive structure which deflects only part of the radiation incident on the front face and originating from an object to be detected, such that the deflected part is propagated as coupled-in radiation in the base body by reflection, until it reaches the coupling-out region and is incident on said coupling-out region, and the coupling-out region deflects at least part of said incident coupled-in radiation, such that the deflected part exits the base body via the front face or the rear face and is incident on the image sensor.

This application provides a mode division multiplexer, which includes a metasurface of an electromagnetic resonance unit that has a plurality of sub-wavelengths disposed in an array. The electromagnetic resonance unit is configured to perform phase modulation on a beam transmitted to the electromagnetic resonance unit, to convert a spatial mode order of the beam. Because a size of the electromagnetic resonance unit is a sub-wavelength, and a pixel size of the electromagnetic resonance unit is smaller than a pixel size of a spatial light modulator in the prior art, crosstalk between different spatial modes after phase modulation performed by the mode division multiplexer is comparatively low. In this way, the crosstalk is comparatively small when beams in different spatial modes are multiplexed into a few-mode/multi-mode fiber. The mode division multiplexer in this application can implement polarization-independent phase modulation.

An electronic device includes a light guide plate, a plurality of light sources, a sealant frame and at least an optical film. The light guide plate includes a first end portion and a second end portion opposite to each other. The plurality of light sources are disposed adjacent to the second end portion and are arranged along the first direction. The sealant frame is disposed adjacent to the first end portion. One of the at least an optical film includes a body portion and a lug portion connected to the body portion, and the lug portion is fixed on the sealant frame. The body portion includes a first side adjacent to the sealant frame and, in a second direction, a shortest distance between the first side and the sealant film is in a range of 0 mm to 0.4 mm.

A display module includes an image light generation device, a light-guiding member, a first reflection surface configured to reflect the imaging light incident via the light-guiding member, a first diffraction element configured to diffract the imaging light, and a second diffraction element configured to diffract the image light and form an exit pupil. The image light is sequentially incident on a first deflection surface, a second deflection surface, a second reflection surface, a third reflection surface, a fourth reflection surface, and a third deflection surface inside the light-guiding member, and a distance from a reference position where an optical axis of the exit pupil and an emission surface intersect to the second deflection surface is longer than a distance from the reference position to the first deflection surface and longer than a distance from the reference position to the second reflection surface.