Provided is a waveguide having a light diffraction unit that diffracts incident light by a multiplex-recorded hologram, in which, in the light diffraction unit, a plurality of holograms having different angles with respect to an incident surface of the waveguide are formed, and when certain parallel light beams are incident, different wavelengths are diffracted by the plurality of holograms.

The display apparatus of the present disclosure includes an imaging light generating device and an optical system on which imaging light emitted from the imaging light generating device is incident. The optical system includes a first optical unit having positive power, a second optical unit having a positive power and including a first diffraction element, a third optical unit having positive power, and a fourth optical unit having positive power and including a second diffraction element forming an exit pupil, the first optical unit, the second optical unit, the third optical unit, and the fourth optical unit being aligned in order along an optical path of the imaging light. The second diffraction element is constituted of a volume hologram and has, in a cross-sectional view of the volume hologram, interference fringes continuously varying in pitch and inclination thereof from one end toward another end of the second diffraction element.

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 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.

A phase converting device capable of use over a broad wavelength range, which may be used for optical beam transformations and combining, conversion of resonator and waveguide modes, correction of aberrations in optical systems, and selection of photons with specific phase profile. This provides significant advantages in high power laser systems. Large-mode-area fibers can be used to provide higher incident powers than can be achieved by single-mode fibers, reducing the number of elements in a system necessary to achieve the desired output. The profiles of these LMA fiber modes can then be converted from the undesired modes into the desired mode while combing their total power into a single beam.

A single-shot Fresnel non-coherent correlation digital holographic device based on a polarization-oriented planar lens, comprising: A polarization-oriented planar lens (1) for wavefront modulation and beam splitting, a focusing element (2), a half-wave plate (3) with a small hole and a polarization imaging camera (4). Incident light passes through the polarization-oriented planar lens (1) and the focusing element (2) and is divided into two beams with different polarizations, that is, focused and parallel or focused and divergent beams, wherein the focused beam passes through the small hole of the half-wave plate (3), the parallel or divergent beam passes through the half-wave plate (3), so as to make the polarization of the two beams consistent behind pass through the half-wave plate (3).

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 optical reflective device referred to as a skew mirror, having a reflective axis that need not be constrained to surface normal, is described. Examples of skew mirrors are configured to reflect light about a constant reflective axis across a relatively wide range of wavelengths. In some examples, a skew mirror has a constant reflective axis across a relatively wide range of angles of incidence. Exemplary methods for making and using skew minors are also disclosed. Skew mirrors include a grating structure, which in some examples comprises a hologram.

A single-shot Fresnel non-coherent correlation digital holographic device based on a polarization-oriented planar lens, comprising: A polarization-oriented planar lens (1) for wavefront modulation and beam splitting, a focusing element (2), a half-wave plate (3) with a small hole and a polarization imaging camera (4). Incident light passes through the polarization-oriented planar lens (1) and the focusing element (2) and is divided into two beams with different polarizations, that is, focused and parallel or focused and divergent beams, wherein the focused beam passes through the small hole of the half-wave plate (3), the parallel or divergent beam passes through the half-wave plate (3), so as to make the polarization of the two beams consistent behind pass through the half-wave plate (3).

The display apparatus of the present disclosure includes an imaging light generating device and an optical system on which imaging light emitted from the imaging light generating device is incident. The optical system includes a first optical unit having positive power, a second optical unit having a positive power and including a first diffraction element, a third optical unit having positive power, and a fourth optical unit having positive power and including a second diffraction element forming an exit pupil, the first optical unit, the second optical unit, the third optical unit, and the fourth optical unit being aligned in order along an optical path of the imaging light. The second diffraction element is constituted of a volume hologram and has, in a cross-sectional view of the volume hologram, interference fringes continuously varying in pitch and inclination thereof from one end toward another end of the second diffraction element.