Provided is a digital holographic image-taking apparatus, including: an illumination portion (10) having a light emission surface (14D) for emitting illumination light toward an object (1), the illumination light having a specific wavelength in a coherent plane waveform; and an image sensor (50) having an pixel array (51) including two-dimensionally arranged pixels, the image sensor (50) capturing an interference pattern generated based on the illumination light having acted on the object (1), in which the following conditional expression is satisfied: 0.0000001<Z.sup.2/S<16, where S represents the area of the light emission surface (14D), and Z represents the distance from the light emission surface (14D) to the pixel array (51).

Transmission and reflection mode VHOEs are designed and fabricated for use in imaging and other applications. These VHOE provide high diffraction efficiency with minimal chromatic aberrations and astigmatism across the bandwidth. The lens provides optical power within the bandwidth centered relative to several wavelengths to magnify (focus or collimate) input light and is transparent for the rest of the image spectrum. In transmission mode, two VHOE are fabricated in such a way as to introduce compensating adjustments that minimize the astigmatism and chromatic aberrations introduced by the bandwidth of the input light. Two VHOEs are required to provide an on-axis imaging system to magnify light to form an image and reduce the chromatic aberrations across the bandwidth and reduce the astigmatism while maintaining high diffraction efficiency (DE). In reflection mode, a single VHOE is configured to act as a mirror at the specified wavelength and bandwidth and to magnify light to form an image and, consequently, has minimal level of astigmatism and chromatic aberration.

Techniques disclosed herein relate to photo-patternable latent-chemistry inorganic materials. An example of the photo-patternable latent-chemistry inorganic materials includes a sol-gel material comprising a solution containing a tin dichloride salt, at least one alcohol containing solvent, and optionally a photo-acid generator or photo-acid. The sol-gel material, upon selective photo-excitation (which forms a latent pattern with latent chemistry in the sol-gel material) and blanket thermal annealing, can form a coating having a formula SnO(n)X(m), where the n:m ratio and/or n-m values of the coating vary across regions of the coating, such that a refractive index of the coating varies across regions of the coating, without affecting the coating's transparency for visible light.

We describe a window assembly comprising: a window pane comprising a glass or plastic sheet; and a layer of holographic recording medium attached to said glass or plastic sheet; wherein said layer of holographic recording medium has recorded within the medium a volume hologram configured to direct light incident onto said glass or plastic sheet to propagate within a thickness of said glass or plastic sheet. In embodiments the volume hologram is fabricated by recording a transmission hologram and shrinking the recorded hologram to convert the transmission hologram to an edge-directing hologram configured to direct light in a direction to be totally internally reflected within the window pane, for example at greater than 40, 50, 60, 70, 75 or 80 to a normal to the surface of the hologram.

In an embodiment a hologram recording system includes an optical system configured to provide first and second beams of electromagnetic radiation, the optical system having a first lens configured to interact with the first beam, a photosensitive recording medium configured to receive the first and second beams and record an interference pattern formed by the first and second beams and an actuation system configured to move a component of the optical system to adjust a position of the first beam relative to the first lens and thereby control an angle of incidence of the first beam at the photosensitive recording medium, wherein the first lens is configured to interact with the second beam, and wherein the actuation system is configured to move a second component of the optical system to adjust a position of the second beam relative to the first lens and thereby control an angle of incidence of the second beam at the photosensitive recording medium.

The present invention is related to an holographic probe device for recording a gabor hologram comprising: a coherent optical fiber bundle comprising a distal end and a proximal end; a recording medium optically coupled to the proximal end of the coherent optical fiber bundle; a light source producing in use a single light beam, illuminating the distal end of the coherent optical fiber bundle and the object to be observed.

An optical element is configured to be worn in front of an eye of a wearer. The optical element has two main surfaces and includes at least one holographic diffusive element having diffusive properties resulting from spatial variations of refractive index of said holographic diffusive element. The spatial variation of refractive index is greater than 0.001 at at least one given wavelength, on a distance less than 30 m. An optical equipment includes the optical element and methods for recording a holographic medium onto an optical lens.

A method includes providing a radiation with a predetermined intensity profile. The method also includes providing a photo-sensitive medium layer including a mixture of a photo-sensitive material and an absorbing additive. The absorbing additive has a predetermined non-uniform distribution in at least one of a direction within a film plane or a thickness direction of the photo-sensitive medium layer. The predetermined non-uniform distribution of the absorbing additive is configured to result in a predetermined non-uniform absorption of the radiation. The method also includes exposing the photo-sensitive medium layer to the radiation to form a polymer film. The optical film includes at least one predetermined birefringence variation in at least one of a direction within a film plane or a thickness direction of the polymer film.

A method includes providing a multiplicity of masters, each of the masters having a substrate body and at least one master hologram, selecting a sequence of masters from the multiplicity of masters based on a plurality of holograms to be replicated and arranging the sequence of masters on a first carrier to align upper faces of the masters in a horizontal plane, detachably laminating a light-sensitive composite web on the aligned upper faces, exposing the masters to replicate the master holograms in the light-sensitive composite web, and detaching the exposed composite web from the masters. The masters are detachably incorporated in the first carrier such that a sequence and/or composition of the masters for replicating the plurality of holograms is variable. The masters are incorporated in the first carrier such that two or more faces of the masters are optically accessible for exposure.