The present invention suggests a holographic optical element which forms a pattern according to a transmissive hologram recording method based on a multi-diverging object beam and a reference beam, a method for generating the same, and a screen device including the holographic optical element. The holographic optical element according to the present invention includes a base film and a pattern which is formed on the base film by using a transmissive hologram recording method based on a multi-diverging object beam and a reference beam.

Techniques to improve image quality in holography utilizing lenses made from materials with non-quantized anisotropic electromagnetic properties, such as birefringent materials, to advantageously split an incoming beam of light into two coincident beams with different focal lengths that interfere with one another and thus create holograms free of electro-optical or pixelated devices are disclosed for microscopy and other applications. The use of thin birefringent lenses and single crystal alpha-BBO lenses are introduced. Corresponding systems, methods and apparatuses are described.

According to one aspect, the invention concerns an optical imaging device (20) for an object (OBJ) by off-axis holography comprising a light source (21) adapted for emitting an illumination wave (E.sub.I) on the object, in transmission or reflection, and an assembly formed by one or more thick Bragg gratings (22) for receiving a wave (E.sub.O) coming from the object thus illuminated and for deflecting a first component (E.sub.R) of the wave coming from the object, called the reference wave, and to allow a second component (E.sub.S) of the wave coming from the object, called the signal wave, to pass without deflection in such a way that the deflected reference wave presents predetermined deflection angles with respect to the non-deflected signal wave defined in two perpendicular planes. The imaging device according to the first aspect further comprises a two-dimensional detection device (23) for acquiring an interferogram resulting from the interference between said deflected reference wave and said signal wave and a computing unit for determining, from said interferogram, an amplitude and phase distribution of the signal wave in the plane of the object (hologram).

A system for making a holographic medium for use in generating light patterns for eye tracking includes a light source configured to provide light and a beam splitter configured to separate the light into a first portion of the light and a second portion of the light that is spatially separated from the first portion of the light. The system also includes a first set of optical elements configured to transmit the first portion of the light for providing a first wide-field beam onto an optically recordable medium and one or more diffractive optical elements configured to receive the second portion of the light and project a plurality of separate light patterns onto the optically recordable medium for forming the holographic medium.

A method includes providing light from a light source and separating the light into a first portion of the light and a second portion of the light that is spatially separated from the first portion of the light. The method also includes transmitting the first portion of the light through a first set of optical elements to provide a first wide-field beam, transmitting the second portion of the light through a second set of optical elements to provide a second wide-field beam that is spatially separated from the first wide-field beam, and transmitting the second wide-field beam through a third set of optical elements to provide a plurality of separate light patterns. The method further includes concurrently projecting the first wide-field beam and the plurality of separate light patterns onto an optically recordable medium to form a holographic medium.

A system for making a holographic medium for use in generating light patterns for eye tracking includes a light source configured to provide light and a beam splitter configured to separate the light into a first portion of the light and a second portion of the light that is spatially separated from the first portion of the light. The system also includes a first set of optical elements configured to transmit the first portion of the light for providing a first wide-field beam onto an optically recordable medium, a second set of optical elements configured to transmit the second portion of the light for providing a second wide-field beam, and a plurality of parabolic reflectors optically coupled with the second set of optical elements and configured to receive the second wide-field beam and project a plurality of separate light patterns onto the optically recordable medium for forming the holographic medium.

This application discloses an in-line system and method for measuring the optical performance of an HOE in motion during a roll-to-roll fabrication process.

Provided is a digital holographic imaging apparatus, comprising: an illumination portion (10) having an illumination light emission surface (32i) for emitting coherent light of a specific wavelength as illumination light toward an object (1) side relative to the illumination light emission surface (32i), and a reference light emission surface (32r) for emitting the coherent light, as reference light, in a direction opposite to the illumination light; and an image sensor (50) located on the reference light emission surface (32r) side of the illumination portion (10) and imaging an interference pattern between object light having been modulated by the object (1) and passed through the illumination portion (10) and the reference light of the illumination light, the image sensor (50) having a pixel array (51) comprising two-dimensionally aligned pixels.

A method of structured illumination digital holography includes: (a) providing a structured illumination generating unit and binarization random number encoding unit to generate a coded structured illumination pattern; (b) sampling at least two patterns with phase shift which synthesized as a single structured illumination pattern to be encoded; (c) forming a single digital hologram, and wavefront reconstructing the single digital hologram; (d) performing a compressive sensing approach to recover the object wave with at least two phase shift patterns; and (e) reconstructing the separation of overlap spectrum, to obtain an image covering bandpass spectrum with different high frequency and low frequency.

A system for measuring vibrations of a surface (VSURF) of a mechanical part (M), comprising a source (SOURCE) of radiation (L), a first separator element (ELI) configured to define a first incident ray (LB1) and a reference ray (RLB), a shaping module (DOEM) producing a second incident ray (LB2) from said first incident ray (LB1), and an optical element (OE) capable of an interferential addition of the reference ray (RLB) and a ray produced by a reflection of said second incident ray (LB2) on said surface (VSURF), the shaping module (DOEM) comprising one or more diffracting optical elements (DOE1, . . . , DOEn), each comprising at least one diffraction structure (FSTRUCT) diffracting all or part of the first incident ray (LB1) so as to illuminate a chosen surface of the mechanical part.