A method for three-dimensional imaging of a sample (302) comprises: receiving (102) interference patterns (208) acquired using light-detecting elements (212), wherein each interference pattern (208) is formed by scattered light from the sample (302) and non-scattered light from a light source (206; 306), wherein the interference patterns (208) are acquired using different angles between the sample (302) and the light source (206; 306); performing digital holographic reconstruction applying an iterative algorithm to change a three-dimensional scattering potential of the sample (302) to improve a difference between the received interference patterns (208) and predicted interference patterns based on the three-dimensional scattering potential; wherein the iterative algorithm reduces a sum of a data fidelity term and a non-differentiable regularization term and wherein the iterative algorithm includes a forward-backward splitting method alternating between forward gradient descent (108) on the data fidelity term and backward gradient descent (110) on the regularization term.

A display device includes a display panel and a window member provided on the display panel. The window member includes a plastic window, a first hard coating layer provided on the plastic window, and a second hard coating layer provided on the first hard coating layer. A surface water contact angle of the second hard coating layer may be in a range of 90 degrees to 117 degrees.

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).

To reduce an influence of stray light and stably record/reproduce high-quality data in holographic recording/reproduction. A holographic memory device includes an optical system that guides a reference beam to an optical information recording medium at a desired angle of incidence, a control part that controls the angle of incidence of the reference beam generated in the optical system, and a lens part that images the reference beam in a desired position of the optical information recording medium. Further, at least a first light beam at a first angle and a second light beam at a second angle different from the first angle are output from the optical element, and the optical element is provided so that the first light beam may propagate within an effective diameter of the lens part and the second light beam may propagate to an outside of the effective diameter of the lens part.

An example hologram device may include a target holographic view of an encoded holographic image representing an alignment target; and a plurality of non-target holographic views of the encoded holographic image, each non-target holographic view indicating a position relative to the target holographic view.

A method for producing holograms with a multiplicity of holographic prescriptions from a single master is provided. A multiplicity of holographic substrates each containing a first hologram is stacked on a second holographic recording medium substrate. The first hologram is designed to diffract light from a first direction into a second direction. When expose to illumination from the first direction zero order and diffracted light from each first hologram interfere in the second holographic recording medium substrate forming a second hologram. The second hologram is then copied into a third holographic recording medium substrate to provide the final copy hologram.

Microscope (2) comprising a coherent light source (4) producing a coherent light beam (7), a light beam guide system (6) comprising a beam splitter (14) configured to split the coherent light beam (7) into a reference beam (7a) and a sample illumination beam (7b), a sample holder (18) configured to hold a sample (1) to be observed, a sample illumination device (28) configured to direct the sample illumination beam (7b) through the sample and into a microscope objective (37), a beam reuniter (16) configured to reunite the reference beam and sample illumination beam after passage of the sample illumination beam through the sample to be observed, and a light sensing system (8) configured to capture at least phase and intensity values of the coherent light beam downstream of the beam reuniter.

A display device includes a light source, a waveguide element, a liquid crystal coupler, a first holographic optical element and a second holographic optical element. The light source is configured to emit light. The waveguide element is located above the light source. The liquid crystal coupler is located between the waveguide element and the light source. The first holographic optical element is located on a top surface of the waveguide element, in which the liquid crystal coupler is configured to change an incident angle that the light emits to the first holographic optical element. The second holographic optical element is located on the top surface of the waveguide element, and there is a first distance in a horizontal direction between the first holographic optical element and the second holographic optical element, in which the second holographic optical element is configured to diffract the light to the waveguide element below.

The layered generation of at least one volume grating in a recording medium by way of exposure, the recording medium having at least one photosensitive layer which is sensitized for a presettable wavelength of the exposure light. Each volume grating is generated in the recording medium by at least two wave fronts of coherent light capable of generating interference, the wave fronts being superposed in the recording medium at a presettable depth, at a presettable angle and with a presettable interference contrast. The depth and the thickness of the refractive index modulation and/or transparency modulation of a volume grating in the recording medium is controlled by depth-specific control of the spatial and/or temporal degree of coherence of the interfering wave fronts in the direction of light propagation.

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.