Techniques related to generating holographic images are discussed. Such techniques include application of a hybrid system including a pre-trained deep neural network and a subsequent iterative process using a suitable propagation model to generate diffraction pattern image data for a target holographic image such that the diffraction pattern image data is to generate a holographic image when implemented via a holographic display.

Provided is a holographic display apparatus including a light source configured to emit light; a spatial light modulator configured to sequentially generate hologram patterns for modulating the light and to sequentially reproduce frames of hologram images based on the hologram patterns; and a controller configured to provide hologram data signals to the spatial light modulator, the hologram data signals being used to sequentially generate the hologram patterns. The controller is configured to further provide, to the spatial light modulator, diffraction pattern data signals for forming periodic diffraction patterns for adjusting locations of the hologram images to be reproduced on a hologram image plane, the diffraction pattern data signals being configured to move the periodic diffraction patterns on the spatial light modulator along a predetermined direction for each of the frames.

A beam steering method and device are provided. The beam steering method includes outputting, from a hologram recording medium on which a plurality of signal light beams having different steering information are recorded, signal light beam having specific steering information, by making reference light having a specific characteristic incident on the hologram recording medium. The method further includes obtaining information about an object existing in the external environment based on the output signal light.

The present invention discloses a reflective holographic storage method and device, in which a reflection layer is plated on a back side of a holographic storage medium, and a new reference light is formed by utilizing the reflection layer, so that a phase conjugate reproduction light of a hologram is obtained. According to the invention, a recording device and a reading device can be provided on the same side of a medium, thereby obtaining a more compact system, reducing design difficulty, improving system stability, and improving the SNR (signal-noise ratio) of reproduction light by the interference between reproduction light and a conjugate reproduction light.

A grating coupler may be fabricated by exposing a photopolymer layer to grating forming light for forming periodic refractive index variations in the photopolymer layer. The photopolymer layer may be exposed to apodization light for reducing an amplitude of the periodic refractive index variations in a spatially-selective manner. The apodization may also be achieved or facilitated by subjecting outer surface(s) of the photopolymer layer to a chemically reactive agent that causes the refractive index contrast to be reduced near the surface(s) of application. The apodized refractive index profile of the gratings facilitates the reduction of optical crosstalk between different gratings of the grating coupler.

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 (Δn), therefore control of side lobe magnitude may be achieved by controlling the distribution of Δn. The distribution of Δn 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 Δn.

Optical systems having comb-shifted sets of holograms across different regions of a grating medium are disclosed. A first set of holograms may be formed in a first region of the grating medium and a second set of holograms may be formed in a second region of the grating medium. Each of the holograms in the first set may have a different respective grating frequency from a first set of grating frequencies. Each of the holograms in the second set may have a different respective grating frequency from a second set of grating frequencies. The second set of grating frequencies may be located within adjacent frequency gaps between the grating frequencies in the first set of grating frequencies. Comb-shifted sets of holograms may be used to perform pupil equalization, output coupling, input coupling, cross coupling, or other operations.

The present disclosure provides an apparatus and method for fabricating optical devices. The apparatus includes a support table having process chambers and a laser used to direct a beam along a propagation path to each of the process chambers. A central mirror is centrally disposed among the process chambers and is rotatable to reflect the beam to each of the process chambers for processing. A beam splitter is disposed within each of process chambers, each beam splitter is used to receive beams from the central mirror and emits a first beam in a first direction and a second beam in a second direction. A first mirror directs the first beam to a device and a second mirror directs the second beam to the device. Each of the first and second mirror is rotatable in at least three axes.

An interference imaging device includes a light interference generator that includes: a light wave splitter configured to reflect a part of incident light and to allow a remaining part of the incident light to pass through; a phase modulator configured to modulate a phase of incident light that has passed through the light wave splitter; and a reflector configured to reflect the phase-modulated incident light from the phase modulator so that the reflected, phase-modulated incident light overlaps with incident light that has been reflected by the light wave splitter.

An image reproduction device reproduces an image including N different parameters of a wavelength range or the like, and includes: a multiple hologram acquisition part that acquires N to 2N multiple holograms obtained by multiplex-recording interference patterns for each parameter; a parameter selection part that selects the parameters one by one; a hologram generation part that generates a computer generated hologram containing two lightwaves having the selected parameter, from the multiple hologram; and a lightwave restoration part that restores one of the two lightwaves from the computer generated hologram.