Techniques to improve image quality in holography utilizing lenses made from materials with non-quantized anisotropic electromagnetic properties, such as birefringent materials, to advantageously split an incoming beam of light into two coincident beams with different focal lengths that interfere with one another and thus create holograms free of electro-optical or pixelated devices are disclosed. Corresponding systems, methods and apparatuses are described.

A three-dimensional light modulator, of which the pixels are combined to form modulation elements. Each modulation element can be coded with a preset discrete value such that three-dimensionally arranged object points can be holographically reconstructed. The light modulator is characterized in that assigned to the pixels of the modulator are beam splitters or beam combiners which, for each modulation element, combine the light wave parts modulated by the pixels by means of refraction or diffraction on the output side to form a common light beam which exits the modulation element in a set propagation direction.

A backlight unit and a holographic display apparatus including the same are provided. The backlight unit includes a light guide plate and a uniformity changing element. The uniformity changing element has a light-incident surface and a light-exiting surface facing the light-incident surface, and the uniformity changing element receives the light output from the light guide plate through the light-incident surface, changes uniformity of the received light from the light guide plate and outputs the received light with the change in the uniformity of the received light through the light-exiting surface.

A spatial light modulator (SLM) includes a first liquid crystal panel and a second liquid crystal panel that are oppositely configured, and a polarization adjustment part configured between the first liquid crystal panel and the second liquid crystal panel. An alignment direction of the first liquid crystal panel is parallel to an alignment direction of the second liquid crystal panel. The first liquid crystal panel is configured to perform a phase modulation on incident linear-polarized light. The polarization adjustment part is configured to rotate, by a preset angle, a polarization direction of linear-polarized light exited from the first liquid crystal panel. The second liquid crystal panel is configured to adjust a polarization state of linear-polarized light exited from the polarization adjustment part to adjust an amplitude of exited light.

Provided is an augmented reality device. The augmented reality device includes a first projection assembly and a first display assembly. The first display assembly is disposed on a light exit side of the first projection assembly. The first projection assembly includes a first scanner, a first laser, and a first lens group. The first display assembly includes a first holographic diffraction grating and a first lens. An exposure device is also provided.

Methods, apparatus, devices, and systems for displaying three-dimensional objects by individually diffracting different colors of light are provided. In one aspect, a system includes a display having a plurality of display elements and an optical device configured to diffract a plurality of different colors of light to the display. The optical device is configured such that, when the plurality of different colors of light is incident on the optical device, the optical device separates light of individual colors of the different colors while suppressing crosstalk between the different colors.

An apparatus and method are introduced to produce a hologram of an object from electromagnetic radiation, such as incoherent light, received from the object. The electromagnetic radiation is received by a receiving assembly and transformed into a plurality of co-linear co-propagating beams with different focal distances. The interference of the plurality of beams is enabled by projecting components of each beam along a common polarization direction. The interference patterns thus formed are recorded and then processed to form the hologram of the object.

An optical apparatus includes a plurality of lenses including a first lens affixed to an optics mount holder which is adjustably affixed to an alignment channel part. The optical axis of the first lens passes through a hollow area of the alignment channel part. The lens is mounted on the optics mount holder which is adjustably affixed to one end of the alignment channel part with a plurality of adjustable fasteners. A method is provided for aligning the optical apparatus.

A light projection apparatus is provided comprising: a source of light; a switchable grating on a first substrate; and a diffractive optical element. Light is diffracted at least once by the switchable grating and is diffracted at least once by the DOE.

A complex light modulator including a first polarization plate, a second polarization plate provided, an amplitude modulator provided between the first polarization plate and the second polarization plate, a phase modulator provided between the amplitude modulator and the second polarization plate, and color filters provided between the amplitude modulator and the phase modulator.