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.

A light detection and ranging system arranged to scan a scene is provided. A light source outputs light having a first characteristic. A spatial light modulator receives output light from the light source and outputs spatially-modulated light in accordance with computer-generated holograms represented thereon. A light detector receives light having the first characteristic from the scene and outputs a light response signal. A holographic controller is arranged to output a plurality of computer-generated holograms to the spatial light modulator. Each computer-generated hologram is arranged to form structured light having a corresponding pattern within the scene. The holographic controller is further arranged to change the pattern of the structured light formed by at least one of the plurality of computer-generated holograms.

A holographic projector comprises an image processing engine arranged to, a hologram engine and a display engine. The image processing engine is arranged to receive a source image for projection. The source image comprises a first colour component and a second colour component. The image processing engine is further arranged to form a first colour secondary image from the first colour component by nulling alternate pixel values of the first colour component in accordance with a first checkerboard pattern. The image processing engine is further arranged to form a second colour secondary image from the second colour component by nulling alternate pixel values of the second colour component in accordance with a second checkerboard pattern. The first checkerboard pattern is opposite to the second checkerboard pattern. The hologram engine is arranged to determine a first colour hologram corresponding to the first colour secondary image and a second colour hologram corresponding to the second colour secondary image. The display engine is arranged to form a first colour holographic reconstruction from the first colour hologram and a second colour holographic reconstruction from the second colour hologram.

Disclosed are a holographic display method and a holographic display device. The holographic display method includes: acquiring an area of Nth diffraction order corresponding to an eye position; according to the area of Nth diffraction order, calculating a holographic complex amplitude distribution corresponding to a window of Nth diffraction order to obtain window hologram information, a function of the holographic complex amplitude distribution being expressed by C(m, n)=A(m, n)*exp[i(m, n)/N]; encoding the window hologram information; and according to the encoded window hologram information, loading the encoded window hologram information in the area of Nth diffraction order to display a hologram.

A method for producing a hologram (1), (1) for security elements (1a) and/or security documents (1b). One or more virtual hologram planes (10) are arranged in front of and/or behind one or more virtual models (20) and/or one or more virtual hologram planes (10) are arranged such that they intersect one or more virtual models (20). One or more virtual light sources (30) are arranged on one or more partial regions of the surface (21) of one or more of the virtual models (20). One or more virtual electromagnetic fields (40) are calculated starting from at least one of the virtual light sources (30) in one or more zones (11) of the one or more virtual hologram planes (10). In the one or more zones (11), in each case, a virtual total electromagnetic field (41) is calculated on the basis of the sum of two or more, of the virtual electromagnetic fields (40) in the respective zone (11). One or more phase images (50) are calculated from the virtual total electromagnetic fields (41) in the one or more zones (11). A height profile (60) of the hologram (1) is calculated from the one or more phase images (50) and the height profile (60) of the hologram (1) is incorporated into a substrate (2) to provide the hologram (1).

A device for producing a subwavelength hologram. The device comprises a metasurface layer attached to a substrate. The metasurface layer includes an array of plasmonic antennas that simultaneously encode both wavelength and phase information of light directed through the array to produce a hologram. The wavelength is determined by the size of the antennas, and the phase is determined by the orientation of the antennas.

There is herein defined optics (e.g. an array of optics) forming an optical beam to either produce a collimated or diverging/converging beam emerging from a virtual source point to illuminate a hologram. There is also described an optical beam illuminating a reflection hologram from the front and a further configuration where an optical beam combined with a holographic optical element (HOE) minor enables rear illumination of a reflection hologram.

Methods and systems and components made according to the methods and systems, are disclosed relating to the generation of a holographic image, including a color-containing holographic image, generated exclusively optically addressing information to a projection system.

A method of holographic projection includes projecting at least one calibration image. The method includes performing the following steps for each calibration image in order to determine a plurality of displacements vectors at a respective plurality of different locations on the replay plane: projecting the calibration image onto the replay plane using a first colour holographic channel by displaying a first hologram on a first spatial light modulator and illuminating the first spatial light modulator with light of the first colour; projecting the calibration image onto the replay using a second colour holographic channel by displaying a second hologram on a second spatial light modulator and illuminating the second spatial light modulator with light of the second colour, the first and second hologram corresponding to the calibration image; determining the displacement vector between the light spot formed by the first colour holographic channel and the light spot formed by the second colour holographic channel; and pre-processing an image for projection using the second colour holographic channel in accordance with the plurality of determined displacement vectors.

A method for producing a volume hologram with at least one first area in a first color and at least one second area in a second color includes, providing a volume hologram layer made of a photopolymer; arranging a master with a surface structure on the volume hologram layer; exposing the master using coherent light, wherein light which is incident on at least one first partial area of the surface of the master is diffracted or reflected in the direction of the at least one first area of the volume hologram layer and light which is incident on at least one second partial area of the surface of the master is diffracted or reflected in the direction of the at least one second area of the volume hologram, and wherein the light diffracted or reflected by the first and second partial areas differs in at least one optical property.