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.

An optical reflective device referred to as a skew mirror, having a reflective axis that need not be constrained to surface normal, is described. Examples of skew mirrors are configured to reflect light about substantially constant reflective axes across a relatively wide range of wavelengths. In some examples, a skew mirror has substantially constant reflective axes across a relatively wide range of angles of incidence. Exemplary methods for making and using skew mirrors are also disclosed. Skew mirrors include a grating structure, which in some examples comprises a hologram.

A lightguide structure for illumination, detection and/or holographic representation includes at least one planar lightguide for guiding electromagnetic radiation of at least a first spectrum, at least one illumination arrangement located on the first side face of the lightguide, and at least one holographic outcoupling structure for coupling out electromagnetic radiation guided in the lightguide structure. The light radiated in by the illumination arrangement can have a large angular range, the holographic outcoupling structure having a small angular range. Also provided is a production method for such a lightguide structure and to an operating element comprising a lightguide structure.

A method for displaying an image viewable by an eye, the image being projected from a portable head worn display, comprises steps of: emitting a plurality of light beams of wavelengths that differ amongst the light beams; directing the plurality of light beams to a scanning mirror; modulating in intensity each one of the plurality of light beams in accordance with intensity information provided from the image, whereby the intensity is representative of a pixel value within the image; scanning the plurality of light beams in two distinct axes with the scanning mirror to form the image; and redirecting the plurality of light beams to the eye using a holographic optical element acting as a reflector of the light beams, whereby the redirecting is dependent on the wavelength of the light beam, to create for each light beam an exit pupil at the eye that is spatially separated from the exit pupils of the other light beams.

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.

The present disclosure relates to apparatuses and methods for performing in-line lens-free digital holography of objects. At least one embodiment relates to an apparatus for performing in-line lens-free digital holography of an object. The apparatus includes a point light source adapted for emitting coherent light. The apparatus also includes an image sensing device adapted and arranged for recording interference patterns resulting from interference from light waves directly originating from the point light source and object light waves. The object light waves originate from light waves from the point light source that are scattered or reflected by the object. The image sensing device comprises a plurality of pixels. The point light source comprises a broad wavelength spectrum light source and a pinhole structure. The image sensing device comprises a respective narrow band wavelength filter positioned above each pixel that filters within a broad wavelength spectrum of the point light source.

An optical reflective device referred to as a skew mirror, having a reflective axis that need not be constrained to surface normal, is described. Examples of skew mirrors are configured to reflect light about substantially constant reflective axes across a relatively wide range of wavelengths. In some examples, a skew mirror has substantially constant reflective axes across a relatively wide range of angles of incidence. Exemplary methods for making and using skew mirrors are also disclosed. Skew mirrors include a grating structure, which in some examples comprises a hologram.

We describe a window assembly comprising: a window pane comprising a glass or plastic sheet; and a layer of holographic recording medium attached to said glass or plastic sheet; wherein said layer of holographic recording medium has recorded within the medium a volume hologram configured to direct light incident onto said glass or plastic sheet to propagate within a thickness of said glass or plastic sheet. In embodiments the volume hologram is fabricated by recording a transmission hologram and shrinking the recorded hologram to convert the transmission hologram to an edge-directing hologram configured to direct light in a direction to be totally internally reflected within the window pane, for example at greater than 40, 50, 60, 70, 75 or 80 to a normal to the surface of the hologram.

A hologram recording device includes a light outputting unit that sequentially outputs multiple laser beams such that the laser beams are coaxially aligned, the laser beams having different wavelengths and being emitted from multiple laser beam sources, an optical system that generates a reference beam and an object beam, with which a hologram is recorded, from each of the laser beams output from the light outputting unit, and an adjusting unit that adjusts a relative position of a recording medium and a focus position of the object beam generated from each of the laser beams having different wavelengths so that the object beam is focused on a surface of the recording medium when the hologram recording device records multiple holograms in a wavelength multiplex recording by sequentially applying the object beams and the reference beams to the recording medium.

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.