Systems, devices, and methods for spatial multiplexing in holographic optical elements (HOEs) are described. A spatially-multiplexed HOE includes multiple spatially-separated holographic regions and each spatially-separated region applies a respective optical function to light that is incident thereon. An exemplary application as a spatially-multiplexed holographic combiner (SMHC) in a scanning laser-based wearable heads-up display (WHUD) is described. In this exemplary application, a scanning laser projector directs multiple light signals over the area of the SMHC and the SMHC converges the light signals towards multiple spatially-separated exit pupils at or proximate the eye of the user. The particular exit pupil at the eye of the user towards which any particular light signal is converged by the SMHC depends on the particular region of the SMHC upon which the light signal is incident. Such may be useful in engineering particular eyebox and/or user interface display configurations in the operation of the WHUD.

For comfortable viewing of a 3-D scene at various viewing angles, a display having a large tracking range for a variable viewer distance is required. A controllable light-influencing element deflects light in coarse steps in a viewer range. Within said steps, the light is deflected by a further controllable light-influencing element continuously or with fine gradation. The light modulation device is suitable in holographic or autostereoscopic displays for guiding the visibility ranges of the image information to be displayed so as to follow the eyes of the viewers.

A holographic display apparatus includes: 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 holographic interferometer, comprising: at least one imaging device capturing an interference pattern created by at least two light beams; and at least one aperture located in an optical path of at least one light beam of the at least two light beams; wherein the at least one aperture is located away from an axis of the at least one light beam, thus transmitting a subset of the at least one light beam collected at an angle range.

An optical device including a hologram recording medium that can reproduce an image of a reference member and an irradiation unit that emits a coherent light beam to the optical device. The irradiation unit includes a light source for emitting a coherent light beam and a scanning device capable of adjusting a reflection angle of the coherent light beam emitted from the light source and that makes a reflected coherent light beam scan the hologram recording medium. The light source has light sources for emitting coherent light beams having different wavelength ranges. The hologram recording medium has a plurality of recording areas to be scanned with a plurality of coherent light beams reflected by the scanning device, respectively. Each of the plurality of recording areas has an interference fringe that diffracts a coherent light beam of the corresponding wavelength range.

Systems, devices, and methods for combined angle- and wavelength multiplexing in holographic optical elements (HOE) are described. An angle- and wavelength-multiplexed HOE includes multiple angle-multiplexed sets of wavelength-multiplexed holograms. Each set of wavelength-multiplexed holograms includes at least two holograms that are each responsive to a different wavelength of light. Each angle-multiplexed set of wavelength-multiplexed holograms includes a respective set of wavelength-multiplexed holograms that are all responsive to light that is incident thereon with and angle of incidence that is within a particular range. An example application is described in which an angle- and wavelength-multiplexed HOE is used as a holographic combiner in a wearable heads-up display, where angle-multiplexing provides multiple spatially-separated exit pupils in the eyebox of the display and wavelength-multiplexing provides multiple colors to each respective exit pupil.

Proposed are an image reproduction device, an image reproduction method, and a digital holography device, by which the calculation load is reduced and a time required to reproduce an object image from hologram image data is shortened, compared with a conventional technology. An image reproduction device (17) can reproduce an object image or a phase image thereof from hologram image data without performing conventional two-dimensional Fourier transform or two-dimensional inverse Fourier transform. Since no two-dimensional Fourier transform or no two-dimensional inverse Fourier transform is performed, the calculation load can be accordingly reduced, and a time required to reproduce an object image from hologram image data can be accordingly shortened, compared with a conventional technology.

Embodiments described herein relate to lens-free imaging. One example embodiment may include a lens-free imaging device for imaging a moving sample. The lens-free imaging device may include a radiation source configured to emit a set of at least two different wavelengths towards the moving sample. The lens-free imaging device is configured to image samples for which a spectral response does not substantially vary for a set of at least two different wavelengths. The lens-free imaging device may also include a line scanner configured to obtain a line scan per wavelength emitted by the radiation source and reflected by, scattered by, or transmitted through the moving sample. The line scanner is configured to regularly obtain a line scan per wavelength. Either the radiation source or the line scanner is configured to isolate data of the at least two different wavelengths.

A method for displaying a hologram to a variable direction including using circuitry to determine a direction from a holographic projector to a viewer for projecting a hologram to a viewer, and projecting a hologram in the determined direction, in which the projecting the hologram includes reflecting from a same mirror as the determining the direction of the viewer, and the circuitry controls the projecting the hologram to a direction corrected for a difference in direction between a projecting unit and a tracking unit relative to the mirror. Related apparatus and methods are also described.

A system for recording a digital hologram of an object comprises: a coherent source intended to illuminate the object and thus produce a wave diffracted by the object; and a digital sensor intended to record the digital hologram of the object. It furthermore comprises a spatial phase modulating assembly able to produce in the plane of the sensor a plurality of duplicates of the wave diffracted by the object, the duplicates being offset from each other but overlapping partially, these duplicates forming on the sensor a digital hologram of the object, this hologram being what is referred to as a self-reference hologram.