To obtain a more accurate image by improving a utilization efficiency of light energy while at the same time suppressing with a simpler method distortion that may occur in an inline hologram when a plurality of lights having different wavelengths are used, an observation device (1) according to the present disclosure includes a light source part (11) in which a plurality of light emitting diodes (101) having different light emission wavelengths with a length of each light emission point being smaller than 100λ (λ: light emission wavelength) are arranged such that a separation distance between the adjacent light emitting diodes is equal to or smaller than 100λ (λ: light emission wavelength); and an image sensor (13) installed so as to be opposed to the light source part with respect to an observation target object.

This application relates to a see-through head-mounted display using recorded substrate-guided holographic continuous lens (SGHCL) and a microdisplay with narrow spectral band source or laser illumination. The high diffraction efficiency of the volume SGHCL creates very high luminance of the virtual image.

An in-line holographic microscope can be used to analyze a video stream to track individual colloidal particles' three-dimensional motions. The system and method can provide real time nanometer resolution, and simultaneously measure particle sizes and refractive indexes. An assay using the holographic microscope for holographic particle characterization directly detect viruses, antibodies and related targets binding to the surfaces of specifically functionalized micrometer-scale colloidal probe beads. The system detects binding of targets by directly measuring associated changes in the bead's diameter without the need for downstream labeling and analysis.

An illumination system is arranged to output a light beam for illuminating a scene. The system comprises a spatial light modulator arranged to receive incident light, and to output light comprising a first component and a second component. The first component comprises incident light that is output without modulation by the spatial light modulator. The second component comprises incident light that is spatially-modulated according to a hologram and output by the spatial light modulator. A control device is operable to control the proportion of light output by the spatial light modulator that corresponds to the second component.

There is disclosed herein a display device comprising a picture generating unit, a waveguide pupil expander and a viewer-tracking system. The picture generating unit comprises a first display channel, a second display channel and a controller. The first display channel is arranged to output first spatially-modulated light of a first colour. The first spatially-modulated light corresponds to a first picture. The second display channel is arranged to output second spatially-modulated light of a second colour. The second spatially-modulated light corresponding to a second picture. The controller is arranged to drive the first display channel and second display channel. The waveguide pupil expander comprises a pair of parallel reflective surfaces. The waveguide pupil expander defines an input port and a viewing window. The input port is arranged to receive the first spatially-modulated light and the second spatially-modulated light. The viewing window is an area or volume within which a viewer may view the first picture and the second picture. The pair of parallel reflective surfaces is arranged to guide the first spatially-modulated light and the second spatially-modulated light from the input port to the viewing window by a series of internal reflections. The reflectivity of a first reflective surface of the pair of parallel reflective surfaces is provided by a graded coating. The graded coating is partially transmissive to light of the first colour and light of the second colour. The transmissivity of the graded coating is non-achromatic. The viewer-tracking system is arranged to determine a viewing position within the viewing window. The controller is arranged to maintain as substantially constant the colour balance of the first and second picture as seen from the viewing position based on the viewing position determined by the viewer-tracking system.

There is provided a holographic projector comprising a hologram engine and a controller. The hologram engine is arranged to provide a hologram comprising a plurality of hologram pixels. Each hologram pixel has a respective hologram pixel value. The controller is arranged to selectively-drive a plurality of light-modulating pixels so as to display the hologram. Displaying the hologram comprises displaying each hologram pixel value on a contiguous group of light-modulating pixels of the plurality of light-modulating pixels such that there is a one-to-many pixel correlation between the hologram and the plurality of light-modulating pixels.

A lighting device for vehicles, and in particular headlamps, having a light source unit, and having a holographic unit for the generation of a given light distribution. The holographic unit has a hologram on the basis of a photo-sensitive material, onto which the holographic information is applied by means of an exposure process. The hologram is formed by a multitude of hologram segments. The hologram segments are each assigned a separate light source of the light source unit. The hologram segments serve to generate the given light distribution. Herein, holographic information is applied to the hologram segments depending on different wavelengths and different angles of the light source assigned to the hologram segments.

A beam steering method and device are provided. The beam steering method includes outputting, from a hologram recording medium on which a plurality of signal light beams having different steering information are recorded, signal light beam having specific steering information, by making reference light having a specific characteristic incident on the hologram recording medium. The method further includes o obtaining information about an object existing in the external environment based on the output signal light.

A holographic imaging device is disclosed. In one aspect, the holographic imaging device comprises an imaging unit comprising at least two light sources, wherein the imaging unit is configured to illuminate an object by emitting at least two light beams with the at least two light sources. A first and second light beams have different wave-vectors and wavelengths. The holographic imaging device further comprises a processing unit configured to obtain at least two holograms of the object by controlling the imaging unit to sequentially illuminate the object with respectively the first light beam and the second light beam, construct at least two 2D image slices based on the at least two holograms, wherein each 2D image slice is constructed at a determined depth within the object volume, and generate a three-dimensional image of the object based on a combination of the 2D image slices.

Systems, devices, and methods for aperture-free hologram recording are described. 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.