A bilayer photonic crystal photoswitch thin-film device having the optical characteristics of both 2D and 3D photonic crystals, and a preparation method thereof are provided. When the bilayer photonic crystal photoswitch thin-film device is rotated periodically, different colors can be observed at a fixed rotation angle, that is, the device has the attribute of changing colors by means of rotation, and can thus realize the opening and closing of an optical path. The bilayer photonic crystal photoswitch thin-film new device has broad application prospects in the fields of photoswitches, optical waveguides, optical prisms, warming signs, anti-counterfeiting and information coding, etc.

An optical device for projecting light beams that is able to interact with a pixelated light source comprising a plurality of selectively activatable emitting elements. The device successively includes, in the direction of the path of the light rays, a first optical unit, a pupil and a second optical unit. The first optical unit includes an output diopter located at a first distance (d.sub.1) from the pupil, and the second optical unit includes an input diopter interface located at a second distance (d.sub.2) from the pupil, the second distance (d.sub.2) being substantially identical to the first distance (d.sub.1). The first unit includes a converging lens, and the second unit includes a doublet of lenses one of which is made of flint glass and the other of which is made of crown glass.

An optical device for projecting light beams that is able to interact with a pixelated light source comprising a plurality of selectively activatable emitting elements. The device successively includes, in the direction of the path of the light rays, a first optical unit, a pupil and a second optical unit. The first optical unit includes an output diopter located at a first distance (d.sub.1) from the pupil, and the second optical unit includes an input diopter interface located at a second distance (d.sub.2) from the pupil, the second distance (d.sub.2) being substantially identical to the first distance (d.sub.1). The first unit includes a converging lens, and the second unit includes a doublet of lenses one of which is made of flint glass and the other of which is made of crown glass.

A metasurface optical device includes a substrate, a nano-structure layer, and a chromatic aberration adjustment layer. The nano-structure layer is formed on a side of the substrate and includes a plurality of nano-structure units. The chromatic aberration adjustment layer includes a stepped structure. The material of the chromatic aberration adjustment layer is different from the substrate material.

A metasurface optical device includes a substrate and a nano-structure layer. The nano-structure layer is arranged on the substrate and includes a plurality of photonic crystal units. Each photonic crystal unit includes a plurality of nano-structure units arranged on the substrate such that an energy bandgap is formed in a cross-section of the photonic crystal unit parallel to the substrate. The energy bandgap surrounds the center area of the cross-section.

Provided is a meta-optical device including a substrate, a first meta-structure layer provided on the substrate, the first meta-structure layer including a first nanostructure having a sub-wavelength shape dimension and a first peripheral material provided adjacent to the first nanostructure, a second meta-structure layer provided on the first meta-structure layer, the second meta-structure layer including a second nanostructure having the sub-wavelength shape dimension and a second peripheral material provided adjacent to the second nanostructure, and a first functional layer provided between the first meta-structure layer and the second meta-structure layer, the first functional layer including a first-first layer having an etch rate that is lower than an etch rate of the second peripheral material, and a first-second layer having a refractive index that is different from a refractive index of the first-first layer.

A method, an apparatus, and a device for determining parameters of a fisheye lens are provided. The fisheye lens includes a meta-lens including a first surface and a second surface, and the first and second surfaces are each provided with a plurality of columnar structures. The method includes: obtaining a focal length and a projection mode of a fisheye lens to be designed; determining a light angle offset of each columnar structure based on the focal length and the projection mode; determining a phase distribution of the columnar structure based on the light angle offset of the columnar structure; and determining a size of the columnar structure according to the phase distribution of the columnar structure. The fisheye lens may achieve a relatively large viewing field in a short distance.

Structured beams, Bessel beams, Laguerre Gaussian beams, and focused Gaussian are used as a natural waveguide and its group velocity can be subluminal (slower than the speed of light) as compared to a Gaussian beam in free space. A free space dispersion relation for a Bessel beam, i.e., the dependence of its wavenumber on its angular frequency, is outlined from which the Bessel beam's subliminal group velocity is derived. For reasonable conditions a Bessel light beam has associated parameters that allow slowing near a critical frequency. The application of Bessel beams for a natural optical buffer in free space is presented. Optical transitions and selection rules in materials are altered by structured light carrying orbital angular momentum (OAM). Nano antennas are used to enhance the interactions of structured light.

A meta-lens includes a first layer that is arranged on a substrate and that includes a plurality of first nanostructures and a second layer including a plurality of second nanostructures separately arranged from the first nanostructures. The meta-lens may focus light of a plurality of wavelengths or light of a wide wavelength bandwidth due to the arrangement of the nanostructures in a multilayer structure.

An optical system of a head-mounted display (HMD) system that includes a diffractive optical element coupled to a display, for example, via lamination or a suitable optically clear adhesive. The optical system may include a reflective polarizer and a quarter-wave plate that, together with the diffractive optical element, form a catadioptric or “pancake” configuration that focuses light from a display system to an eye of a user of the head mounted display system.