A holographic 3D recording device includes: a photorefractive crystal and a microlens array. The microlens array includes an array face and a side face. The microlens array is provided in a light path from an object to be photographed to the photorefractive crystal such that first light of object emitted through a diffuse reflection of the object to be photographed passes through the array face of the microlens array and becomes second light of object that is emitted to the photorefractive crystal. The photorefractive crystal is configured to receive the second light of object emitted by the microlens array and reference light, respectively, and save therein an interference fringe formed by the reference light and the second light of object. The first light of object and the reference light are coherent light.

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.

A volume holographic imaging system, apparatus, and/or method enables the projection of a two-dimensional (2D) slice of a four-dimensional (4D) probing object. A 4D probing source object is illuminated to emit or scatter an optical field. A holographic element having one or more recorded holograms receives and diffracts the optical field into a diffracted plane beam having spectral information. A 4-f telecentric relay system includes a pupil filter on the relayed conjugate plane of the volume hologram and images the pupil of the volume hologram onto the front focal plane of the collector lens. A collector lens focuses the diffracted plane beam to a 2D slice of the 4D probing source object. The focused 2D slice is projected onto a 2D imaging plane. The holographic element may have multiple multiplexed holograms that are arranged to diffract light from the corresponding slice of the 4D probing source object.

A volume holographic imaging system, apparatus, and/or method enables the projection of a two-dimensional (2D) slice of a four-dimensional (4D) probing object. A 4D probing source object is illuminated to emit or scatter an optical field. A holographic element having one or more recorded holograms receives and diffracts the optical field into a diffracted plane beam having spectral information. A 4-f telecentric relay system includes a pupil filter on the relayed conjugate plane of the volume hologram and images the pupil of the volume hologram onto the front focal plane of the collector lens. A collector lens focuses the diffracted plane beam to a 2D slice of the 4D probing source object. The focused 2D slice is projected onto a 2D imaging plane. The holographic element may have multiple multiplexed holograms that are arranged to diffract light from the corresponding slice of the 4D probing source object.

A holographic 3D recording device includes: a photorefractive crystal and a microlens array. The microlens array includes an array face and a side face. The microlens array is provided in a light path from an object to be photographed to the photorefractive crystal such that first light of object emitted through a diffuse reflection of the object to be photographed passes through the array face of the microlens array and becomes second light of object that is emitted to the photorefractive crystal. The photorefractive crystal is configured to receive the second light of object emitted by the microlens array and reference light, respectively, and save therein an interference fringe formed by the reference light and the second light of object. The first light of object and the reference light are coherent light.