Methods, devices and systems for improved fabrication and measurement of holographic elements are described. One example method includes directing a reference and an object beam toward a holographic material for formation of a diffraction grating in the holographic material, and blocking one of the reference or the object beams to prevent the beam from reaching the holographic material for at least a portion of time during which the diffraction grating is being formed. During the blockage of the beam, a power level of a diffracted beam associated with the reference or the object beam that is not being blocked is measured. Based on the measured power level, it is then determined whether a particular diffraction grating efficiency is reached. The described techniques enable real-time measurement of diffraction grating efficiency as the grating is being formed and enable improved fabrication of holographic elements hat must meet precise diffraction grating efficiency requirements.

A method and apparatus for processing hologram image data capable of optimizing image quality of a hologram image are provided. The image processing method includes receiving input image data, reading a header included at a predetermined location in the input image data, and generating hologram data configured to display a hologram image by performing a Fourier calculation and pixel encoding on the input image data based on at least one parameter recorded in the header, wherein the at least one parameter recorded in the header includes at least one of depth information, scale information, and gamma information.

A device and a method for manufacturing holographic optical elements. The device includes at least two partial light beams and one interference light beam, one deformable mirror in each case per partial light beam, a control unit, which is configured to actuate the deformable mirrors to adapt a wavefront of the partial light beam, and a holographic film. The deformable mirrors are situated so as to each reflect precisely one partial light beam and to direct the reflected partial light beam on the holographic film, and the interference light beam being directed on the holographic film to interfere with the reflected partial light beams so as to simultaneously generate at least two holographic optical elements.

A spatial modulator is provided on a plane conjugate to a sample plane on which a sample is to be placed. The spatial modulator spatially modulates illumination light irradiated to the sample 2 or object light that has passed through or that has been reflected by the sample. A dark-field optical system removes the non-scattered light component of the first object light affected by the spatial light modulator so as to generate second object light. An image sensor records a hologram based on the second object light. A calculation processing apparatus combines complex amplitude information based on the modulation pattern supplied to the spatial light modulator and complex amplitude information based on the hologram with respect to the second object light so as to acquire a phase distribution originating from the sample.

A holographic storage optical system includes a storage medium, a recording unit, an imaging unit and a servo unit. The recording unit comprises a movable Fourier lens, by which the positions and irradiation angles of a signal light spot and a reference light spot are adjusted. The servo unit comprises a calibration lens for adjusting the positions of a servo light spot in the horizontal and vertical directions so that the servo light spot is located at an optimal position relative to signal light beam and reference light beam. The beam calibrating method comprises (1) before recording a data hologram, burning a calibration hologram at a calibration holographic positioning mark on an optical track of a storage medium; (2) before reproducing the data hologram, using the calibration hologram to optimize the signal-to-noise ratio of the hologram reproduced by adjusting the calibration lens and the Fourier lens.

A method of performing phase retrieval and holographic image reconstruction of an imaged sample includes obtaining a single hologram intensity image of the sample using an imaging device. The single hologram intensity image is back-propagated to generate a real input image and an imaginary input image of the sample with image processing software, wherein the real input image and the imaginary input image contain twin-image and/or interference-related artifacts. A trained deep neural network is provided that is executed by the image processing software using one or more processors and configured to receive the real input image and the imaginary input image of the sample and generate an output real image and an output imaginary image in which the twin-image and/or interference-related artifacts are substantially suppressed or eliminated. In some embodiments, the trained deep neural network simultaneously achieves phase-recovery and auto-focusing significantly extending the DOF of holographic image reconstruction.

Provided is a hologram printing method and apparatus using a hologram medium light efficiency map. A hologram printing method according to an embodiment emits a laser to a hologram medium, acquires an image by photographing light diffracted from the hologram medium, generates a light efficiency map of the hologram medium from the acquired image, and records hogels on the hologram medium by referring to the generated light efficiency maps of the hologram medium. Accordingly, light efficiency is measured on each hogel area, and hologram printing is performed by adjusting an intensity of a laser of each wavelength according to a hogel, so that uniformity of luminance and color of a hologram printing result can be enhanced.

An optical device includes an optical component (e.g., a polarization volume hologram, a geometric phase device, or a polarization-insensitive diffractive optical element) having a uniform thickness and configured to modify a wavefront of a light beam that includes light in two or more wavelengths visible to human eyes, where the optical component has a chromatic aberration between the two or more wavelengths. The optical device also includes a metasurface on the optical component. The metasurface includes a plurality of nanostructures configured to modify respective phases of incident light at a plurality of regions of the metasurface, where the plurality of nanostructures is configured to, at each region of the plurality of regions, add a respective phase delay for each of the two or more wavelengths to correct the chromatic aberration between the two or more wavelengths.

Techniques related to generating holographic images are discussed. Such techniques include application of a machine learning model to the target image to generate data that is used to enable the determination of a phase pattern via a wave propagation model. The wave propagation model is used to generate holographic data, which is then adjusted according to one or more constraints associated with the holographic display that will be used to generate a holographic image based on the adjusted holographic data.

A system includes a diffractive optical element configured to receive a first beam and a second beam interfering with one another to generate a first interference pattern. The diffractive optical element is also configured to forwardly diffract the first beam and the second beam to output a third beam and a fourth beam. The third beam and the fourth beam interfere with one another to generate a second interference pattern. The system also includes a detector configured to detect the second interference pattern.