A method for producing a holographic optical element (HOE) that is provided for projection in a projection system. A hologram is recorded by the fact that a first Gaussian beam and a second Gaussian beam are caused to interfere on a holographic film for at least two different configurations. The first Gaussian beam is a reference beam that, for the at least two different configurations, is identical to a reconstruction beam with which the HOE is reconstructed. The second Gaussian beam is furthermore an object beam that, upon reconstruction of the HOE utilizing the reconstruction beam, is identical to a projection beam that is used in the projection system for projection. For the at least two different configurations, at least one beam property that depends respectively on predefined projection properties of the projection system is predefined for the second Gaussian beam.

Example embodiments relate to methods and imaging systems for holographic imaging. One embodiment includes a method for holographic imaging of an object. The method includes driving a laser using a current which is below a threshold current of the laser. The method also includes illuminating the object using illumination light output by the laser. Further, the method includes detecting an interference pattern formed by object light, having interacted with the object, and reference light of the illumination light.

Apparatuses and methods for improved reconstructions of electron-based holograms are disclosed herein. An example method at least includes forming a hologram of a sample and a known object, forming a reconstruction of the known object using a reconstruction algorithm, comparing the reconstruction of the known object to a reference reconstruction of the known object, and adjusting the reconstruction algorithm based on the comparison of the reconstruction of the known object to the reference reconstruction of the known object. The example method may further include forming a reconstruction of the sample using the adjusted reconstruction algorithm.

A holographic optical element and a method for producing the same are disclosed herein. In some embodiments, a method includes illuminating a first surface of a photopolymer resin layer, where the photopolymer resin layer comprises a photopolymer resin, illuminating a second surface of the photopolymer resin layer through a retardation layer disposed in the second surface, wherein the second surface is opposite the first surface, and recording an interference pattern in the photopolymer resin layer, wherein the interference pattern is created by interference between the first parallel laser beam and the second parallel laser beam. The holographic optical element is produced using a retardation layer to prevent an unwanted interference pattern from being formed in the process of recording an interference pattern in a photopolymer resin layer.

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.

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.

Techniques related to generating holographic images for a holographic heads up display 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 an iterative propagation feedback model. The iterative propagation feedback model is used to generate a feedback strength value, which is then used to generate a phase diffraction pattern for presentation at a holographic plane of the heads up display.

A dark field digital holographic microscope and associated metrology method is disclosed which is configured to determine a characteristic of interest of a structure. The dark field digital holographic microscope includes an illumination branch for providing illumination radiation to illuminate the structure; a detection arrangement for capturing object radiation resulting from diffraction of the illumination radiation by the structure; and a reference branch for providing reference radiation for interfering with the object radiation to obtain an image of an interference pattern formed by the illumination radiation and reference radiation. The reference branch has an optical element operable to vary a characteristic of the reference radiation so as to reduce and/or minimize variation in a contrast metric of the image within a field of view of the dark field digital holographic microscope at a detector plane.

There is provided an apparatus and method for generating a hologram through measuring intensity and a phase of a complex light wavefront that is output from a complex modulation spatial light modulator (SLM); determining characteristic information of the complex light wavefront by analyzing the measured intensity and phase of the complex light wavefront; creating distortion correction information for correcting distortion of the complex light wavefront from an artificial neural network by inputting the characteristic information to the artificial neural network; and feeding back the distortion correction information to the complex modulation SLM.

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.