G03H1/265

OPTICAL INFORMATION REPRODUCING DEVICE AND OPTICAL INFORMATION REPRODUCING METHOD
20170270961 · 2017-09-21 ·

An optical information reproducing device which reproduces information from an optical information storage medium recording, as the information, a hologram which is an interference pattern between a signal beam and a reference beam, the hologram corresponding to an angle of the reference beam being a page, the device includes an image distortion learning unit which detects, based on a two-dimensional reproduction signal generated by reproducing the page, a marker which is a known pattern for detecting a position of two-dimensional data relating to the page, and learns a distortion amount which is the difference between a position of the detected marker and an ideal position, a detection unit which detects, based on the distortion amount, position information on the marker from the page, and an image distortion correction unit which corrects, based on the position information on the marker detected by the detection unit, an image distortion in the page.

Dynamic aperture holography

Methods and systems for performing dynamic aperture holography are described. Examples include a method of recording multiple holograms in a photosensitive recording medium, where multiple signal beam angular apertures used to record the multiple holograms differ from each other. The multiple signal beam angular apertures can facilitate using a larger range of reference beam angular apertures. The multiple holograms are typically multiplexed, and examples of dynamic aperture holography enable packing the multiplexed holograms more densely in the recording medium. Some dynamic aperture holography systems include monocular objective lens architecture.

Virtual image display with curved light path

A display includes a projector configured to provide light of a virtual image, a waveguide into which the light of the virtual image is injected at an injection angle by the projector, and a combiner disposed along the waveguide and configured to redirect the light of the virtual image. The waveguide is configured to emit the light at a point established by the injection angle. The combiner is further configured to allow ambient light from beyond the waveguide to pass through the combiner. The waveguide constrains the light of the virtual image through total internal reflection along a curved path for the light between the projector and the combiner.

Optical Systems with Resolution-Enhancing Holographic Elements
20210405380 · 2021-12-30 ·

An electronic device may include an optical system that redirects light from a display module towards an eye box along an optical path. The optical path may include a holographic coupler and a resolution-enhancing holographic element. The holographic element may include a first set of holograms and the coupler may include a second set of holograms. The first set of holograms may be characterized by a first set of selectivity curves having first primary lobes. The second set of holograms may be characterized by a second set of selectivity curves having second primary lobes that overlap the first primary lobes. This may configure the holographic element to narrow the second selectivity curves by diffracting some of the light out of the optical path, thereby optimizing the resolution of images in the light provided to the eye box.

OPTICAL SECURITY DEVICE
20210379921 · 2021-12-09 ·

An optical security device (1) comprising a recorded or encoded representation of an optically variable image (40), the image (40) being reconstructable and viewable for security, authentication or identification purposes, the device (1) comprising: an optical structure (30) in which there is recorded or encoded a representation of the optically variable image (40) in the form of a plurality of discrete portions (e.g. 50) of the complete image (40) to be reconstructed, wherein the respective said plurality of portions (e.g. 50) of the optically variable image (40) can, when reconstructed, only be viewed in their totality by viewing the said image (40) at or over a plurality of different viewing angles or angle ranges (70) relative to the optical structure (30) and/or at or over a plurality of different angles or range of angles of illumination of the optical structure (10), and wherein the size, in at least one dimension, direction, axis or plane, of the complete image (40), when reconstructed, is greater than the corresponding size, in the same, or the respective same, dimension, direction, axis or plane, of a part of the optical structure (30) having the said plurality of portions (e.g. 50) of the image (40) collectively recorded or encoded therein.

COHERENT SKEW MIRRORS

Systems and methods for performing coherent diffraction in an optical device are disclosed. An optical device may include a grating medium with a first hologram having a first grating frequency. A second hologram at least partially overlapping the first hologram may be provided in the grating medium. The second hologram may have a second grating frequency that is different from the first grating frequency. The first and second holograms may be pair-wise coherent with each other. A manufacturing system may be provided that writes the pair-wise coherent holograms in a grating medium using a signal beam and a reference beam. Periscopes may redirect portions of the signal and reference beams towards a partial reflector, which combines the beams and provides the combined beam to a detector. A controller may adjust an effective path length difference between the signal and reference beams based on a measured interference pattern.

HOLOGRAPHIC DISPLAY APPARATUS

Provided is a holographic display apparatus including: a spatial light modulator that modulates a wavefront of a reference beam to form a hologram image; an optical element arranged to change a position of a viewing window of the hologram image off-axis by a first angle; and an image processor that generates hologram data according to the position of the viewing window of the hologram image and a hologram image to be reproduced, and provides the hologram data to the spatial light modulator. The hologram image formed by the spatial light modulator is viewable from a side of the spatial light modulator.

Polarization holographic microscope system and sample image acquisition method using the same

A polarization holographic microscope system is disclosed. The polarization holographic microscope system can acquire a birefringence image and a three-dimensional phase image with high sensitivity by aperture synthesis of sample beams at various angles, and a sample image acquisition method using the microscope system.

VOLUME HOLOGRAPHIC OPTICAL ELEMENTS WITH EXPANDED ANGULAR ACCEPTANCE
20220187765 · 2022-06-16 ·

The present invention features VHOEs with expanded acceptance angle ranges as well as various systems and methods for fabricating VHOEs with expanded acceptance angle ranges. The VHOE with expanded acceptance angle range may include two or more individual Bragg gratings. In preferred embodiments, the two or more individual Bragg gratings have the same diffraction geometry but with shifted Bragg conditions. Having the same diffraction geometry means when light is incident on the VHOE including two or more individual Bragg gratings, the diffracted light from each of the Bragg gratings is co-linear or overlapping with the diffracted light from the other Bragg gratings. The Bragg condition for each of the Bragg gratings are shifted with respect to each neighboring Bragg grating by an amount up to the acceptance angle range of each individual Bragg grating.

METHOD AND HOLOGRAPHIC APPARATUS FOR THE THREE-DIMENSIONAL REPRESENTATION OF SCENES
20220179360 · 2022-06-09 ·

An apparatus and method for the three-dimensional representation of scenes comprising an illumination device and a spatial light modulation device for modulating incident light. A hologram is encoded into the spatial light modulation device and the hologram is composed of individual sub-holograms, in which an object point of an object of the scene to be reconstructed by the hologram is encoded in each case. The spatial light modulation device is illuminated with substantially coherent light by the illumination device in at least one illumination section. An amplitude distribution and a phase distribution for representing the scene and amplitude values and phase values derived therefrom are determined for encoding the spatial light modulation device. The amplitude of the light incident on the spatial light modulation device in the respective illumination section is set based on at least one parameter at least determined from the amplitude values in this illumination section.