A method for recording a plurality of scatter volume holograms in a photopolymeric recording medium, the method including at least the following steps providing a first laser light source, providing a photopolymeric recording medium including a substrate and a photoactive layer, wherein the photopolymeric recording medium has an index modulation n of at least 0.04 and a thickness d of the photoactive layer of at least 25 m, and irradiating the photopolymeric recording medium with the first laser light beam generated by the first laser light source with a minimum irradiation energy dosage of 3*D.sub.i, D.sub.i being the inhibition dosage of the photoactive layer.

An apparatus for producing an optically variable film includes a laser configured to emit a beam, a telescoping lens section having a first lens and a second lens spaced apart by a first distance and an interferometer configured to direct the beam toward a workpiece. The laser may be operated at a predetermined power level and the first and second lenses are sized and spaced relative to one another to direct the beam onto the workpiece at about 200-230 dots per inch. The workpiece may include a polyethylene terephthalate (PET) layer configured to be ablated by the beam, forming a microstructure in the surface of the layer. The microstructure may be randomized and used to present non-chroma visual effects.

An embodiment of the invention relates to a method for carrying out a time-resolved interferometric measurement comprising the steps of generating at least two coherent waves, overlapping said at least two coherent waves and producing an interference pattern, measuring the interference pattern for a given exposure time, thereby forming measured interference values, and analyzing the measured interference values and extracting amplitude and/or phase information from the measured interference values. In at least one time segment, hereinafter referred to as disturbed time segment, of the exposure time, the interference pattern is intentionally disturbed or destroyed such that the corresponding measured interference values describe a disturbed or destroyed interference pattern. In at least one other time segment, hereinafter referred to as undisturbed time segment, of the exposure time, the interference pattern is undisturbed or at least less disturbed compared to the disturbed time segment such that the corresponding measured interference values describe an undisturbed or less disturbed interference pattern. The measured interference values that were measured during the entire given exposure time, are filtered, wherein those interference values that were measured during the at least one disturbed time segment, are reduced, suppressed or discarded. The filtered interference values are analyzed and the amplitude and/or phase information is extracted from the filtered interference values.

A method for decreasing scatter or crosstalk in holographic elements recorded in self-developing media, comprising exposing a photopolymer recording media to a holographic pattern at a first temperature of said photopolymer recording media, wherein monomer diffusion is substantially reduced at said first temperature, and warming said photopolymer recording media to a second temperature wherein monomer diffusion is enabled.

The present disclosure discloses a method and apparatus for preparing a femtosecond optical filament interference direct writing volume grating/chirped volume grating. The method is characterized in that optical filaments are formed in glass by using femtosecond pulse laser, and plasma is controlled to quickly scan in the glass and etch a volume grating or chirped volume grating structure by adjusting the focal length of convex lens, laser energy and movement of motor machine. The apparatus includes a femtosecond pulse laser module, a pulse chirp management module, a pulse time domain shaping module, a laser separation and interference module, a glass volume grating processing platform module and a camera online imaging module.

The present invention relates to a method and apparatus for holographic recording based on holographic printing technology, and more specifically, to a method and apparatus for holographic recording, in which the hologram is recorded after the deviation in diffraction efficiency for each hogel is pre-compensated for by varying the intensity (luminance) of the object beam for each hogel during the hologram recording in response to a deviation in diffraction efficiency (reconstruction efficiency) for each hogel of a holographic recording surface that occurs when the hologram is reproduced. Accordingly, the reproduction imbalance of a near-eye display (NED) using a holographic optical element (HOE) is resolved by controlling the diffraction efficiency uniform on the entire holographic recording surface when the hologram is reproduced.

An optical data-recording system comprises a laser, a dynamic digital hologram, an electronic controller, and a scanning mechanism. The dynamic digital hologram includes a plurality of holographic zones, and is configured to direct the irradiance received thereon to an optical recording medium. The electronic controller is operatively coupled to the dynamic digital hologram and configured to control the irradiance directed from each of the holographic zones. The scanning mechanism is configured to change a relative positioning of the laser versus the dynamic digital hologram so that each of the holographic zones is irradiated in sequence by the laser.

The invention relates to a method for producing a holographic optical element by providing a recording stack comprising at least one recording element laminated on at least one supporting element, irradiating at least a part of the recording stack with at least one recording beam in an irradiating step, wherein during the irradiating step, the recording stack bends, providing a bending deviation threshold for the recording stack, and adjusting at least one first process parameter such that an expected maximum bending deviation of the recording stack does not exceed the bending deviation threshold, wherein the at least one first process parameter influences the bending behaviour of the recording stack during the irradiating step.

The invention relates to a method for recording a plurality of scatter volume holograms in a photopolymeric recording medium, the method comprising at least the following steps providing a first laser light source, providing a photopolymeric recording medium comprising a substrate and a photoactive layer, wherein the photopolymeric recording medium has an index modulation n of at least 0.04 and a thickness d of the photoactive layer of at least 25 m, irradiating the photopolymeric recording medium with the first laser light beam generated by the first laser light source with a minimum irradiation energy dosage of 3*D.sub.i, D.sub.i; being the inhibition dosage of the photoactive layer, wherein the irradiation of the photopolymeric recording medium is performed such that the light of the irradiating first laser light beam is scattered at scattering centers, the scattering centers being generated by the chemical react ion in the photoactive layer induced by the first laser light beam thus forming a plurality of scatter volume holo grams by interaction between the irradiating first laser light beam and the scattered light of the first laser light beam.

A digital holography device of an embodiment of the present invention includes: an image sensing device which records, in an image sensor and on the basis of an object, a plurality of holograms that correspond to respective different photographic exposure values; and a computer which (i) generates a high dynamic range hologram, which includes pieces of information ranging from low luminance information to high luminance information, by synthesizing the plurality of holograms recorded and (ii) generates a reconstructed image of the object by performing arithmetic processing of phase-shift interferometry, diffraction calculation, and/or the like on the basis of the high dynamic range hologram.