A holographic recording system includes a linear translation stage configured to position a holographic material layer, a light source configured to emit a laser beam, a beam splitting subsystem configured to split the laser beam into a first light beam and a second light beam and direct the second light beam towards the holographic material layer, a spatial-light modulator configured to implement a fringe pattern that modulates the first light beam to generate an object beam, a filter configured to filter the object beam, a demagnification optical subsystem configured to demagnify the object beam, and a switchable grating stack configurable to direct the object beam to a set of directions towards the holographic material layer to interfere with the second light beam. In some embodiments, the switchable grating stack includes a plurality of polarization gratings and/or a plurality of switchable waveplates arranged in a stack.

In the present invention, by providing a hologram displaying apparatus including a light source configured to emit input light, a spatial light modulator configured to modulate the input light into diffracted light, and a plurality of noise filtering elements configured to remove optical noise components from the diffracted light modulated by the spatial light modulator, and display a hologram, an optical path of a light source for displaying the hologram can be drastically reduced while effectively performing spatial filtering.

An optical image generation system including: a spatial light modulator (SLM) configured to receive an input collimated laser beam and modulate the wavefront of the laser beam; one or more optical elements configured to project the modulated laser beam onto a focal plane; a first mirror and a second mirror situated at the focal plane, an edge of the first mirror being adjacent to an edge of the second mirror, the first mirror reflects a first portion of the modulated laser beam in a first direction, the second mirror reflects a second portion of the modulated laser beam in a second direction; and an objective lens projects the first and second portions into a combined image; wherein the zeroth order diffraction is block or suppressed at the center of the focal plane.

A projection device comprises: a spatial light modulator having a display unit whereon a pattern corresponding to a display image is presented; a light source arranged to irradiate the display unit with emission light; a projection optical system arranged on the optical path of the reflected light of the emission light incident on the display unit and projecting projection light with the high order component included in the reflected light removed therefrom; and a projection control unit that causes the display unit to present a composite image that combines an image formed by a virtual lens that focuses the emission light incident on the display unit at a first focus position with the pattern corresponding to the display image, and controls the light source so that the display unit is irradiated with the emission light.

A tunable-liquid-crystal-grating-based holographic true 3D display system comprises a laser, a filter, a beam expander, a semi-transparent semi-reflective mirror, a spatial light modulator, a lens I, a diaphragm, a tunable liquid crystal grating, a polaroid, a signal controller, a lens II and a receiving screen. The laser, the filter and the beam expander are used for generating collimated incident light. The spatial light modulator is loaded with a hologram of a 3D object. The diaphragm is positioned behind the lens I for eliminating a high-order diffracted light in the holographic true 3D display. The tunable liquid crystal grating is located on the back focal plane of the lens I and on the front focal plane of the lens II, and the signal controller is used for synchronously controlling the voltage of the tunable liquid crystal grating and the generation and loading of the hologram.

A holographic display apparatus includes a light guide plate including an input coupler and an output coupler, a holographic image generating assembly configured to generate a holographic image and provide the holographic image to the input coupler of the light guide plate, and an image processor configured to convert source image data based on a point spread function, which is obtained for each pixel of the holographic image on an image plane, to compensate for a blur of the holographic image output through the output coupler.

A holographic display with a spatial light modulator coupled to a pupil-replicating lightguide is disclosed. The spatial light modulator provides a light beam with spatially modulated amplitude and/or phase. The light beam is replicated by the pupil-replicating lightguide into a plurality of portions. The portions interfere at an exit pupil to provide an image for direct observation by a user. An eye-tracking system may be provided to determine the position of the user pupils, and the spatial modulation of the light beam may be adjusted accordingly to make sure that the optical interference of the beam portions at the eye pupils provides the required image.

A holographic display apparatus capable of providing an expanded viewing window and a display method are provided. The holographic display apparatus includes an image processor configured to provide computer generated hologram (CGH) data to a spatial light modulator, wherein the image processor is further configured to generate a hologram data array comprising information of the holographic image to be reproduced at the first resolution or a resolution less than the first resolution, perform an off-axis phase computation on the hologram data array at the second resolution, and then, generate the CHG data at the first resolution.

A near-eye display device includes an image source, a waveguide, and a controller. The waveguide is configured to propagate light received the image source to a user of the near-eye display device, and includes a holographic grating comprising a plurality of angularly multiplexed holograms. The controller is configured to control display of an image via the image source.

Disclosed is a method for processing an input hologram HE associated with an input plane, to obtain an output hologram displayable on a holographic screen placed in a plane called the output plane of a display system, viewable from a viewing plane of the system. The method includes: receiving the input hologram and a position of the input plane; obtaining a first transfer matrix representative of a propagation between the input plane and the viewing plane; obtaining a second transfer matrix representative of a propagation between the viewing plane and the output plane; calculating an overall matrix of transfer of a light field emitted by the input hologram, between the input plane and the output plane, by taking the product of the two matrices; and converting the input hologram into the output hologram by applying an operator dependent of the input hologram and on the screen.