A projection system arranged to receive an image for projection. The image is a colour image comprising a first colour component and a second colour component. The system is arranged to calculate a first hologram of the first colour component and a second hologram of the second colour component. The system is further arranged to add content of the second colour component to the first colour component before calculating the first hologram. The first hologram contains information of the first colour component and information of at least a portion of the second colour component. The system is further arranged to form a first holographic reconstruction by illuminating the first hologram with first colour light and to form a second holographic reconstruction by illuminating the second hologram with second colour light. The first holographic reconstruction changes the chromaticity of the at least a portion of the second colour component.

A holographic image display device according to one embodiment comprises: an image display unit on which a holographic image is displayed; and a spatial impression providing unit which forms a space surrounding the holographic image, and includes a transparent color material such that the space looks colored and the holographic image can be recognized from the outside.

A three-dimensional holographic display device includes a light emitting diode (LED) array including a plurality of light sources controlled to sequentially output light according to a preset pattern, a lens configured to refract light incident from the LED array, a spatial light modulator (SLM) configured to modulate light incident from the lens, and a processor configured to generate a plurality of holographic signals each comprising depth information adjusted according to an arrangement location of each of the plurality of light sources, and for each of the plurality of light sources, control the SLM to modulate the light based on a holographic signal corresponding to the light source.

An apparatus and method for the three-dimensional representation of scenes comprising an illumination device and a spatial light modulation device for modulating incident light. A hologram is encoded into the spatial light modulation device and the hologram is composed of individual sub-holograms, in which an object point of an object of the scene to be reconstructed by the hologram is encoded in each case. The spatial light modulation device is illuminated with substantially coherent light by the illumination device in at least one illumination section. An amplitude distribution and a phase distribution for representing the scene and amplitude values and phase values derived therefrom are determined for encoding the spatial light modulation device. The amplitude of the light incident on the spatial light modulation device in the respective illumination section is set based on at least one parameter at least determined from the amplitude values in this illumination section.

A method to form a three-dimensional photonic crystal template with a gradient structure involves irradiating a photoresist composition of a thickness of at least 15 μm from at least four laser beams to yield a periodic patterned with a percolating matrix of mass in constructive volumes of a cured photoresist composition and destructive volumes of voids free of condensed matter where the proportion of constructive volume displays a gradient from the irradiated surface to the substrate after development. For a given light intensity, photoinitiator concentration in the photoresist composition, and a given thickness, by irradiating for a relatively short period, a three-dimensional photonic crystal template displaying a gradient having greater constructive volume proximal the air interface forms and a relatively long irradiation period results in a gradient having greater constructive volume proximal the substrate.

A method for observing a sample by lensless imaging, in which a sample is positioned between a laser diode and an image sensor, the laser diode being supplied with a supply current whose intensity is less than or equal to a critical value. This critical intensity is determined during preliminary operations, during which the intensity is initially greater than a laser threshold of the diode. By observing the image formed at the image sensor, the intensity is decreased until an attenuation of the interference images on the formed image is observed, the critical intensity corresponding to the intensity at which this attenuation is optimum.

A totagram is produced by an iterative spectral phase recovery process resulting in complete information recovery using special masks and using a reference beam. Using these special masking systems reduce computation time, number of masks, and number of iterations. Adding a reference wave to the iterative process provides better phase recovery systems and aid in the preventing of phase wrapping. The reference wave is added on-axis to provide a well-controlled amplitude. The reference wave is added after the physical or digital transformation system and subtracted before recording the initial amplitude. An additional camera at the input plane records the amplitudes of the original input wave which are used during the iterative process.

A device includes a display configured to generate an image light. The device also includes a waveguide optically coupled with the display and configured to guide the image light to an exit pupil of the device. The waveguide includes a grating including a birefringent material, and a birefringence of the grating is configured to increase along a pupil-expanding direction of the device.

A diffractive optical element, such as a holographic plasma lens, can be made by direction two laser beams so that they overlap in a nonlinear material, to form an interference pattern in the nonlinear material. The interference pattern can modify the index of refraction in the nonlinear material to produce the diffractive optical element. The interference pattern can modify the distribution of plasma for the nonlinear material, which can adjust the index of refraction. A third laser beam can be directed through the diffractive optical element to modify the third laser beam, such as to focus, defocus, or collimate the third laser beam.

Apparatuses and methods for comparative holographic imaging to improve structural and molecular information of reconstructions is disclosed herein. An example method at least includes acquiring a plurality of holograms of a sample, wherein each hologram of the plurality of holograms is acquired at a different electron beam energy, and determining atomic and structural information of the sample based at least on a comparison of at least two of the holograms of the plurality of holograms.