Provided are an improved holographic reconstruction apparatus and method. A holographic reconstruction method includes: obtaining an object hologram of a measurement target object; extracting reference light information from the obtained object hologram; calculating a wavenumber vector constant of the extracted reference light information, and generating digital reference light by calculating a compensation term of the reference light information by using the calculated wavenumber vector constant; extracting curvature aberration information from the object hologram, and then generating digital curvature in which a curvature aberration is compensated for; calculating a compensated object hologram by multiplying the compensation term of the reference light information by the obtained object hologram; extracting phase information of the compensated object hologram; and reconstructing 3-dimensional (3D) shape information and quantitative thickness information of the measurement target object by calculating the quantitative thickness information of the measurement target object by using the extracted phase information of the compensated object hologram.

This application relates to a method of generating three-dimensional (3D) shape information of an object to be measured from an image including intensity information of an object hologram generated by interference between a reference light reflected from an optical mirror and an object light affected by the object. In one aspect, the method includes checking at least one frequency component included in the image and extracting real image components corresponding to a real image from the frequency component. The method also includes generating a correction light and a real image hologram based on the real image components, generating an intermediate hologram based on the correction light, and generating curvature aberration correction information from the intermediate hologram. The method further includes generating a correction hologram based on the curvature aberration correction information and generating the 3D shape information of the object from the correction hologram.

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.

Techniques related to generating holographic images are discussed. Such techniques include application of a pre-trained deep neural network to a target holographic image to generate a feedback strength value for error feedback in an iterative propagation feedback model and generating a diffraction pattern image corresponding to the target holographic image by applying the iterative propagation feedback model based on the target holographic image and using the feedback strength value.

Methods and systems for forming holographic gratings are described herein. The methods and systems may decrease the amount of haze produced during exposure of a holographic recording medium. In some embodiments, the methods and systems include a holographic recording medium; a master hologram containing a grating; and a light source and moveable deflector configured to diffract light through the master hologram into the holographic medium to form a holographic interference pattern. The moveable deflector is configured to move in a direction parallel to the extending direction of the grating. Advantageously, moving the light in this direction allows the holographic interference pattern to remain stationary while there is a spatio-temporal displacement and cancellation of unwanted intensity nonuniformities.

There are provided holographic optical elements (HOEs) and methods of making the same. An example of such methods includes recording a first hologram in a contiguous holographic recording medium of the HOE. The first hologram may receive a beam of light and direct at least a portion of the beam into a light guide to form an incoupled beam. The method also includes recording a second hologram in the contiguous holographic recording medium. The second hologram may receive at least a portion of the incoupled beam and direct the portion of the incoupled beam out of the light guide to form an outcoupled beam. In addition, the method includes affixing the holographic recording medium to the light guide.

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.

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.

A system and method to produce a hologram of a single plane of a three dimensional object includes an electromagnetic radiation assembly to elicit electromagnetic radiation from a single plane of said object, and an assembly to direct the elicited electromagnetic radiation toward a hologram-forming assembly. The hologram-forming assembly creates a hologram that is recorded by an image capture assembly and then further processed to create maximum resolution images free of an inherent holographic artifact.

An illumination unit emits illumination light to a specimen. An image sensor includes multiple pixels arranged in a two-dimensional manner on a photoelectric surface. The image sensor captures an image of a magnitude distribution of an interference pattern formed due to the illumination light that has interacted with the specimen. A limiter limits at least one from among the spatial frequency of the interference pattern formed on the photoelectric surface and the incident angle of the light input to the photoelectric surface.