Exemplary arrangements relate to methods for recording and reproducing holograms. A method of recording a hologram in a thresholded opto-magnetic medium (7) includes producing a collimated recording beam (1) with a pulsed laser. The intensity of the recording beam is selectively modulated by passage through a modulator (2). The recording beam is spatially shaped by passage through a shaping element (15). The shaped modulated recording beam is made convergent by passage through an aspheric lens (4). The convergent beam is deflected bidirectionally with a MEMS mirror (6) that is in operative connection with the modulator, such that multiple disposed locations on a surface of the medium are exposed to a constriction of the convergent shaped recording beam, causing a change in the medium in the locations. Reconstructing the hologram is carried out by illuminating the medium with a collimated laser beam and focusing with a lens, light from the illuminated medium onto a detection matrix. Additional methods of recording and reproducing holograms utilize alternative steps.

A process of forming an identification marking within article formed from an at least partially optically transparent material for identification and validation, said process including the steps of (i) forming an indicia with an at least partially optically transparent material by way of subsurface laser engraving (SSLE); and (ii) forming a plurality of defects within or adjacent indicia within said at least partially optically transparent material resultant of the step of forming the indicia and from localized heating and irregularities in said at least partially optically transparent material, wherein said plurality of defects forms said identification marking

A method and system for forming a holographic structure in a material. The holographic structure is configured to project a selected target image in the far field under illumination of the holographic structure by a laser. The method calculates a modified design for the holographic structure that encodes a unique identifier within the holographic structure for projecting the target image. The method modifies the material by mapping features corresponding to the modified design into the material so as to form the holographic structure. A basic check of the authenticity of the material is performed by checking whether a projected replica of the target image is as expected. A more detailed check of the authenticity of the material is performed by directly inspecting the features in the holographic structure.

An image display system includes a reflecting screen that has a reflecting surface. The reflecting surface includes hologram which reflects narrow bands of spectrum of incident lights toward desired direction. A projection display system includes a reflecting mirror(s) with hologram so that the image can be projected nearly vertical or short distance. This invention can be used as a head-up-display with improved brightness and eliminating ghost noise.

A freeform holographic imaging apparatus includes an imaging table for supporting a substrate, an imaging beam positioned adjacent to the imaging table; and a controller operatively connected to the imaging beam and configured to control a position of the imaging beam with respect to the imaging table. The controller is configured to control the imaging beam to image first and second holographic optical elements on the substrate, wherein each of the first and second holographic optical elements are a single pixel. The first holographic optical element is imaged according to a first parameter set and the second holographic optical element is imaged according to a second parameter set.

A process of forming an identification marking within article formed from an at least partially optically transparent material for identification and validation, said process including the steps of (i) forming an indicia with an at least partially optically transparent material by way of subsurface laser engraving (SSLE); and (ii) forming a plurality of defects within or adjacent indicia within said at least partially optically transparent material resultant of the step of forming the indicia and from localized heating and irregularities in said at least partially optically transparent material, wherein said plurality of defects forms said identification marking.

A direct-write lithography apparatus includes a polarization selector stage configured to vary a polarization orientation angle of light from a light source, a focusing element configured to focus the light from the light source into a spot at a focal plane thereof, and a scanning stage configured to scan the spot in at least two dimensions along a surface of a polarization-sensitive recording medium that is arranged proximate to the focal plane such that neighboring scans substantially overlap. The polarization selector stage and the scanning stage are configured to be operated independently of one another. Related fabrication methods of and optical elements fabricated thereby are also discussed.

An image display system includes a reflecting screen that has a reflecting surface. The reflecting surface includes hologram which reflects narrow bands of spectrum of incident lights toward desired direction. A projection display system includes a reflecting mirror(s) with hologram so that the image can be projected nearly vertical or short distance. This invention can be used as a head-up-display with improved brightness and eliminating ghost noise.