One embodiment provides an apparatus for displaying an image comprising: a first optical substrate comprising at least one waveguide layer configured to propagate light in a first direction, wherein the at least one waveguide layer of the first optical substrate comprises at least one grating lamina configured to extract the light from the first substrate along the first direction; and a second optical substrate comprising at least one waveguide layer configured to propagate the light in a second direction, wherein the at least one waveguide layer of the second optical substrate comprises at least one grating lumina configured to extract light from the second substrate along the second direction, wherein the at least one grating lamina of at least one of the first and second optical substrates comprises an SBG in a passive mode.

A driving module configured for driving a teleconverter lens assembly to move up and down with precision includes a mounting base, a driving assembly connected with the mounting base, and an optical grating sensor. The driving assembly includes a linear motor adapted to be fixedly connected with the teleconverter lens assembly and configured to drive the teleconverter lens assembly to move, and an air cylinder configured to support the teleconverter lens assembly. The optical grating sensor is electrically connected with the linear motor and configured to detect and feedback a position of the teleconverter lens assembly driven by the linear motor in real time. A focusing mechanism including the driving module is also disclosed.

An optical element including a first optical layer, a second optical layer, and a transparent base material, the first optical layer being disposed between the second optical layer and the transparent base material and a diffraction grating being disposed at the interface between the first optical layer and the second optical layer, wherein the refractive index of the d-line of the second optical layer is higher than the refractive index of the d-line of the first optical layer, the Abbe number of the second optical layer is higher than the Abbe number of the first optical layer, the first optical layer is composed of a first resin and inorganic particles dispersed in the first optical layer, and the second optical layer is composed of a second resin having a modulus of elasticity of 0.1 GPa or more and 3.0 GPa or less at 22° C. or higher and 24° C. or lower.

An optical element formed of a plurality of materials includes a middle layer between a base material and a reflecting member so as to suppress stripping, cracking and the like of the optical surface due to the difference in coefficients of thermal expansion among the component materials, in the case where a temperature difference in the service environment or a temperature difference between a manufacturing environment and the service environment is large.

Provided are a hyperspectral sensor and a hyperspectral camera in which influence of external information such as a reflecting material is reduced such that the spectral data accuracy of a subject to be acquired can be improved. In the hyperspectral sensor in which light from a subject is split into light components in a plurality of wavelength ranges by a spectral optical element and each of the light components in the wavelength ranges is received by a sensor array consisting of a plurality of photodetection elements to acquire spectral data in which spectral information of the subject is associated with each of the photodetection elements, a polarization diffraction element that emits polarized light is used as the spectral optical element.

A lamp projecting a starry sky is provided. The lamp projecting the starry sky includes at least one beam generator, a reflecting member with uneven and irregular reflecting surface, a first motor, and at least one first lens. The first motor is connected to the reflecting member through a connecting shaft, the reflecting member is driven to rotate when the first motor rotates, a light beam generated by the beam generator irradiates onto a first side of the reflecting member along an incident light path, and a light beam emitted from the reflecting member forms a moving and layering nebula projection after passing through the at least one first lens. In the lamp, after passing from the reflecting member, the light beam is magnified by the lens, so that the generated starry sky will not be too bright and dazzling, which effectively enhances the layering sense of the starry sky.

An optical device includes a substrate, a surface-relief grating including grooves and ridges formed on or in the substrate, and an overcoat layer in the grooves of the surface-relief grating. The ridges of the surface-relief grating or the overcoat layer includes a plurality of clusters of metal oxide (e.g., TiO.sub.2 or NbO.sub.x) nanoparticles. Each cluster of the plurality of clusters of metal oxide nanoparticles includes metal oxide nanoparticles dispersed in an inorganic barrier that isolates the metal oxide nanoparticles from other materials of the optical device. The ridges of the surface-relief grating or the overcoat layer is made of a resin material that includes a resin with inorganic content, and/or TiO.sub.x or NbO.sub.x nanoparticles including inorganic-containing ligands. A high-energy treatment process can remove organics surrounding the metal oxide nanoparticles and form the barrier layers that surround clusters of metal oxide nanoparticles.

An optical element (11) has an optical surface (20) with a diffraction structure (21). The optical surface (20) is curved such that a distance-to-diameter ratio between a distance A between a deepest point (T) and a highest point (H) and a largest diameter D is greater than 1/10. When producing the optical element (11), firstly a raw optical element having a raw optical surface to be provided with the diffraction structure (21) is provided. The raw optical surface is then coated with a photoresist with the aid of an isotropic deposition method and the photoresist is exposed and then developed. This results in a production method for an optical element with an optical surface having a diffraction structure, which method satisfies stringent requirements made of a structure accuracy when producing the diffraction structure.

To overcome the problem of a diffractive surface having a large, and often excessively large, amount of chromatic aberration, an optical system can use multiple cascaded or sequential diffractive surfaces that, combined, have a reduced amount of chromatic aberration. The optical system can be designed such that all rays traversing the optical system and passing through the diffractive surfaces have an equal optical path length. In the design process, the sets of rays are identified, and the designs of the diffractive surfaces are selected to produce the angular deviations to produce the identified ray paths. In one example, an achromatic lens formed as two annular optical surfaces can receive a collimated incident beam, redirect rays helically at the first surface toward the second surface, and redirect the rays at the second surface toward a focal point. The azimuthal redirection can decrease with increasing distance away from a central axis.

An optical device comprises a waveguide plate, which in turn comprises: an in-coupling element to form first guided light and second guided light by diffracting input light, first expander element to form third guided light by diffracting the first guided light, second expander element to form fourth guided light by diffracting the second guided light, and an out-coupling element to form first output light by diffracting the third guided light, and to form second output light by diffracting the fourth guided light, wherein the out-coupling element is arranged to form combined output light by combining the first output light with the second output light, wherein the in-coupling element has a first grating period for forming the first guided light, and wherein the in-coupling element has a second different grating period for forming the second guided light.