A holographic display system comprises a light source configured to emit at least partially coherent light; a modulator arranged to be illuminated by the at least partially coherent light and to generate a light field which is a quantised representation of a target light field, H; and a spatial filter delimiting an aperture in a Fourier plane. A Fourier transform of the target light field, F(H), substantially does not overlap (i) a Fourier transform of a complex conjugate of the target light field, F(H*), (ii) a Fourier transform of the target light field multiplied by the complex conjugate of the target light field, F(HH*), (iii) a Fourier transform of a square of the target light field, F(H.sup.2), and (iv) a Fourier transform of a square of the complex conjugate of the light field F(H*.sup.2). The aperture substantially corresponds to F(H) in the Fourier plane.

A projection system that facilitates the use of in-situ detection of a change in wavelength, thereby enabling appropriate compensation or corrections to be applied on the fly to improve the quality of the image in the primary image region. In-situ detection in this manner can allow wavelength changes due to both temperature fluctuations and hardware variations to be compensated for simultaneously, thereby reducing the time and expense for end of line hardware testing, and removing the need to perform in-situ mapping of the wavelength as a function of temperature. In this way, the quality of the image provided to a user can be improved in a simpler, more efficient manner.

Systems, devices, and methods for side lobe control in holograms are described. The magnitude of the side lobes of a hologram depends on the distribution of refractive index modulation (n), therefore control of side lobe magnitude may be achieved by controlling the distribution of n. The distribution of n may be controlled by replicating a hologram from a master with two reference beams, where the wavelength and angle of each reference beam, the playback angle of the master hologram, and the thickness of the master hologram, the copy holographic recording medium (HRM), and the recording substrate are carefully chosen to achieve a pattern of meta-interference within the HRM that matches the desired distribution of n.

Systems, devices, and methods for side lobe control in holograms are described. The magnitude of the side lobes of a hologram depends on the distribution of refractive index modulation (n), therefore control of side lobe magnitude may be achieved by controlling the distribution of n. The distribution of n may be controlled by replicating a hologram from a master with two reference beams, where the wavelength and angle of each reference beam, the playback angle of the master hologram, and the thickness of the master hologram, the copy holographic recording medium (HRM), and the recording substrate are carefully chosen to achieve a pattern of meta-interference within the HRM that matches the desired distribution of n.

Systems, devices, and methods for side lobe control in holograms are described. The magnitude of the side lobes of a hologram depends on the distribution of refractive index modulation (n), therefore control of side lobe magnitude may be achieved by controlling the distribution of n. The distribution of n may be controlled by replicating a hologram from a master with two reference beams, where the wavelength and angle of each reference beam, the playback angle of the master hologram, and the thickness of the master hologram, the copy holographic recording medium (HRM), and the recording substrate are carefully chosen to achieve a pattern of meta-interference within the HRM that matches the desired distribution of n.

The present disclosure provides a hologram display device including a spatial light modulator, a lens assembly, and a plurality of backlights. The plurality of backlights are provided at a light incident side of the spatial light modulator, and the lens assembly is provided between the plurality of backlights and the spatial light modulator. The plurality of backlights are configured to emit light having different directions towards the lens assembly, respectively, the lens assembly is configured to guide received light having different directions to the spatial light modulator, and the spatial light modulator is configured to form images at different positions at a light emergent side of the spatial light modulator according to the light having different directions from the lens assembly, respectively.

An information processing apparatus includes a controller that controls formation of an image to be formed in air so that the image and a user do not overlap each other in a space.

There is provided a lighting device arranged to produce a controllable light beam for illuminating a scene. The device comprises an addressable spatial light modulator arranged to provide a selectable phase delay distribution to a beam of incident light. The device further comprises Fourier optics arranged to receive phase-modulated light from the spatial light modulator and form a light distribution. The device further comprises projection optics arranged to project the light distribution to form a pattern of illumination as said controllable light beam.

Systems, devices, and methods for aperture-free hologram recording are described. The apertures typically used for hologram recording create unwanted secondary holograms by diffracting light. Aperture-free hologram recording eliminates these unwanted secondary holograms. Aperture-free hologram recording includes applying a mask to the holographic recording medium. The mask controls the size of the recorded hologram like an aperture but does not create unwanted secondary holograms. Hologram fringes are only present in the desired recording area and a thin boundary region. The mask may be present during recording, or the mask may be used to pre-bleach the holographic recording medium. Pre-bleaching the holographic recording medium renders a portion of the holographic recording medium insensitive to light, the hologram is recorded in the light-sensitive portions of the holographic recording medium.

Systems, devices, and methods for aperture-free hologram recording are described. The apertures typically used for hologram recording create unwanted secondary holograms by diffracting light. Aperture-free hologram recording eliminates these unwanted secondary holograms. Aperture-free hologram recording includes applying a mask to the holographic recording medium. The mask controls the size of the recorded hologram like an aperture but does not create unwanted secondary holograms. Hologram fringes are only present in the desired recording area and a thin boundary region. The mask may be present during recording, or the mask may be used to pre-bleach the holographic recording medium. Pre-bleaching the holographic recording medium renders a portion of the holographic recording medium insensitive to light, the hologram is recorded in the light-sensitive portions of the holographic recording medium.