There is provided a holographic optical element including: a hologram portion including a plurality of groups of unit regions, each group of unit regions of the hologram portion being configured to produce a respective holographic image under a respective light illumination having a respective predetermined wavelength; and a colour filter portion formed on the hologram portion, the colour filter portion including a plurality of groups of unit regions, each group of unit regions of the colour filter portion being arranged on a corresponding group of the plurality of groups of unit regions of the hologram portion, whereby the plurality of groups of unit regions of the colour filter portion is spatially arranged to form a predetermined colour image. There is also provided a method of forming the holographic optical element. There is further provided an article having optical security incorporated therein.

A system includes a plurality of optical identifiers and a reader for the optical identifiers. Each optical identifier has an optical substrate and a volume hologram (e.g., with unique data, such as a code page) in the optical substrate. The reader for the optical identifiers includes a laser, and a camera. The laser is configured to direct laser light into a selected one of the optical identifiers that has been placed into the reader to produce an image of the associated volume holograms at the camera. The camera is configured to capture the image. The captured image may be stored in a digital format by the system.

An image display device of the present disclosure includes an image light generating device, a first, a second, a third, and a fourth optical unit. A first intermediate image is formed between the first and the third optical unit. A pupil is formed between the second and the fourth optical unit. A second intermediate image is formed between the third and the fourth optical unit. An exit pupil is formed at an opposite side of the fourth optical unit from the third optical unit. The image light generating device includes a first, a second, a third light emitting panel, and a color synthesis element. The color synthesis element is constituted of a cross dichroic prism including a first and a second dichroic film that intersect with each other. Each of the first and the second dichroic film does not have a polarization separation characteristic.

Provided is an augmented reality (AR) device based on a waveguide with a holographic diffractive grating structure and an apparatus for recording the holographic diffractive grating structure. The apparatus includes a light source, a beam splitter, a first amplitude filter and a first triangular prism that are arranged on a path of a first light beam, and a second amplitude filter and a second triangular prism that are arranged on a path of a second light beam, in which a first part of the first light beam passes through the first triangular prism without attenuation, a second part of the first light beam passes through the first triangular prism after being attenuated, and the second light beam passes through the second triangular prism after being attenuated, and the holographic diffractive grating structure is recorded between the first triangular prism and the second triangular prism.

A light projection apparatus is provided comprising: a source of light; a switchable grating on a first substrate; and a diffractive optical element. Light is diffracted at least once by the switchable grating and is diffracted at least once by the DOE.

A head-mounted display apparatus according to an aspect of the present disclosure includes an imaging light generating device, a first deflection element including a first deflection section configured to deflect imaging light in a first direction and a second deflection section configured to deflect the imaging light in a second direction, a first diffraction element, and a second diffraction element. When a plane surrounded by the principal ray passing plane, the first principal ray, the second principal ray, and the first deflection section is taken as a first plane, and a plane surrounded by the second deflection section, the first principal ray, the second principal ray, and the first diffraction element is taken as a second plane, the first plane overlaps with at least a part of the second plane when viewed from the third direction and does not overlap with the second plane when viewed from the fourth direction.

A modular routing node includes a single input port and a plurality of output ports. The modular routing node is arranged to produce a plurality of different deflections and uses small adjustments to compensate for wavelength differences and alignment tolerances in an optical system. An optical device is arranged to receive a multiplex of many optical signals at different wavelengths, to separate the optical signals into at least two groups, and to process at least one of the groups adaptively.

The purpose of the present invention is to provide a waveguide, a method for manufacturing the waveguide, and an image display device using the same, which can be applied to incident light with a wide light angle range and a wide wavelength range, and can suppress a decrease in optical efficiency while maintaining high see-through performance. In order to achieve the above purpose, the waveguide has a light diffraction unit that diffracts the incident light by a multiplex-recorded hologram, wherein the light diffraction unit has at least two regions, and the light diffraction unit diffracts light of different wavelengths by the respective regions when certain parallel light ray is incident.

A rotational geometric phase hologram has geometric phase optical elements (GPOEs) serially cascaded along a common optical axis to form a GPOE cascade used for receiving a linearly-polarized light beam and generating output light beams at an exit surface of the last GPOE. Interference occurred in the output light beams creates a polarization interference pattern on the exit surface. A photoalignment substrate, when positioned in close proximity to the exit surface, records the pattern. Advantageously, each GPOE is rotatable about the common optical axis. Respective rotation angles of the GPOEs are determined according to a spatially-varying linear polarization orientation distribution selected to be generated for the polarization interference pattern. Particularly, the respective rotation angles are reconfigurable to provide the periodicity required for the spatially-varying linear polarization orientation distribution over a range of allowed periodicities while keeping the periodicity of spatially-varying optic axis orientation distribution of each GPOE to be fixed.

An optical imaging system employing a device containing a sequence of first (pre-dispersor) and second (main) volume holograms configured to operate as a sequence of optical diffractive elements possessing different blazing curves. A pre-cursor hologram has a thickness smaller than the thickness of the following, disperser hologram, and a comparatively broad spectral selectivity as compared to that of the main hologram, allowing the pre-cursor to diffract light in transmission within a very large range of the angles of incidence. The use of the combination of the pre-cursor and the main holograms not only implements selective imaging of the chosen target object at every angle at which various portions of the object are seen at the optical system, but also facilitates the spectroscopic measurements of such object.