2740results about "Diffraction gratings" patented technology

A metalens for focusing light is described. The metalens includes a library of elements for varying the propagating phase of the focusing light over at least a 2π radians range, where the library of elements is arranged in a sub-wavelength pattern that defines spacings between the elements. Each spacing exhibiting temperature-dependent spacing changes within a temperature range and each element in the library of elements includes: a refractive index exhibiting a temperature-dependency within the temperature range, a shape exhibiting a temperature-dependency within the temperature range, and a size exhibiting a temperature-dependency within the temperature range. The metalens also includes a phase profile defined by a combination of the refractive index, shape, and size of each element in the library, and the sub-wavelength pattern of the library of elements. The metalens also includes a focal length defined by the phase profile, the focal length exhibiting a temperature-dependency within the temperature range.

The invention belongs to the technical field of laser, and discloses a grating multiplexing spectrum synthesis system, which comprises a beamlet dense array, a diffraction grating and a turn-back mirror, each beamlet emitted by the beamlet dense array is diffracted by the diffraction grating and then is emitted in the form of convergent light, and the light is reflected twice by the turn-back mirror to form a light beam; each laser sub-beam is incident on the diffraction grating again along the opposite direction parallel to the original light, the sub-beams converge into one point on the diffraction grating by adjusting the distance between the turn-back mirror and the diffraction grating, and at the moment, the incident angle of each sub-beam is equal to the diffraction angle diffracted from the diffraction grating for the first time; and the diffraction angles of the sub-beams subjected to the second diffraction on the diffraction grating are equal and equal to the incident angle of the sub-beams subjected to the first diffraction, that is, the synthesized light beam is emitted along the direction parallel to and opposite to the direction of the light beam emitted from the sub-beam dense array. The invention provides a spectrum synthesis system which is simple in structure, easy in engineering implementation and compact in volume.

The invention belongs to the technical field of optical materials, and discloses a holographic polymer dispersed liquid crystal composition, a holographic grating and a preparation method. The composition comprises the following components in parts by mass: 0.5-1.5 parts of a photoinitiator, 2-5 parts of a co-initiator, 15-20 parts of a first monomer, 15-20 parts of a second monomer, 10-15 parts of a third monomer, 10-15 parts of a solvent and 10-20 parts of mixed liquid crystal. Wherein the first monomer is a monofunctional acrylic monomer, the second monomer is a bifunctional acrylic monomer, the third monomer is a polyfunctional acrylic monomer, the mixed liquid crystal comprises 10-25 wt% of a monomer liquid crystal and 75-90 wt% of a nematic liquid crystal, and the monomer liquid crystal contains fluorine as a benzene ring substituent and contains cyano or isothiocyano as an end group. Through cooperation of the monomer liquid crystal and the nematic liquid crystal in the mixed liquid crystal and cooperation of fluorine atoms and cyano / isothiocyano groups in the monomer liquid crystal, the holographic grating prepared from the composition has the characteristics of low haze and high diffraction efficiency, and the grating can be thinner, so that the requirements of light weight and clearness of AR glasses can be met.

The invention provides a continuous depth gradually-changing grating structure based on a silicon carbide substrate and a preparation method thereof. The preparation method comprises the following steps: forming a sacrificial layer with gradually-changing thickness on the silicon carbide substrate; etching is carried out by adopting a two-step plasma etching process; and polishing the surface through a plasma polishing process. According to the invention, the gradient sacrificial layer is combined with two-step plasma etching, and a high-precision continuous depth gradient grating structure is realized on the silicon carbide substrate, so that the diffraction requirements of RGB three-color wavelengths are met; the micro-groove defect in the etching process is eliminated, the problem that the depth-to-width ratio and the surface quality cannot be considered in the traditional process is solved, and a key technical support is provided for mass production of the single-layer full-color optical waveguide; the transmission loss of the optical waveguide is reduced by controlling the surface roughness; and the product yield is improved, the production cost is reduced, and the method is suitable for large-scale production.

The invention discloses an external cavity tunable laser linewidth compression system for realizing wavelength phase locking based on mutual injection of gain chips. The external cavity tunable laser linewidth compression system comprises a red light semiconductor laser main gain chip, a first collimation optical system, a blazed grating, a tuning rotating mirror, a reflector, a power supply driving system and a double-path feedback amplification system, the double-path feedback amplification system comprises a first secondary gain chip, a second secondary gain chip, a second collimation optical system, a third collimation optical system and a polarization-free beam splitter prism; and the red light semiconductor laser main gain chip, the first secondary gain chip and the second secondary gain chip are all connected with the power supply driving system. Therefore, the technical problems of low output infrared light power, poor stability and narrow mode-hopping-free tuning range in the prior art are solved, and high-power, narrow-linewidth, high-stability and large-range mode-hopping-free continuous tuning red light output can be realized.

The invention discloses a preparation method of a polymer dispersed liquid crystal holographic grating with s polarization high diffraction characteristics, and belongs to the technical field of holographic optics. Raw materials comprise 60-90% of a thiol-ene monomer, 10-40% of liquid crystals, a photoinitiator accounting for 1.25% of the mass of the monomer, and a coinitiator accounting for 1.56% of the mass of the monomer. Light with the wavelength of 532 nm and the light intensity of 5-30 mW / cm < 2 > is used for carrying out double-interference photoetching to generate photochemical reaction so as to generate the polymer grating film, and the light is s polarized light. Under the optimal recording condition, delta n under s polarization can reach 1.93 * 10, and delta n under p polarization can reach 1.21 * 10. In combination with morphology analysis, it is found that refractive index modulation strongly depends on the proportion of a liquid crystal-rich phase to a polymer-rich phase in the grating. It is proved that the size of liquid crystal microdroplets formed by holographic recording is larger due to low recording intensity, and therefore the threshold driving voltage of the HPDLC grating is reduced.

The invention provides an acrylate monomer with a high refractive index and a preparation method and application thereof, the acrylate monomer has a structure as shown in a formula G1, G2 or G3, the refractive index of the acrylate monomer is 1.75 or above, so that a holographic recording medium has higher sensitivity and higher diffraction efficiency, and the holographic recording medium can be applied to the field of holographic recording. The holographic recording medium is used for a holographic grating, so that the holographic grating has high diffraction efficiency and high refractive index modulation degree.

To allow systems for manufacturing waveguide cells in accordance with various embodiments to be configured and implemented in many different ways.SOLUTION: In many embodiments, various deposition mechanisms are used to deposit a layer(s) of an optical recording material(s) onto a transparent substrate. A second transparent substrate can be provided, and the three layers can be laminated to form a waveguide cell. A suitable optical recording material can vary widely depending on a given application. In some embodiments, the optical recording material deposited has a similar composition throughout a layer. In a number of embodiments, the optical recording material spatially varies in composition, enabling formation of optical elements with varying characteristics. Regardless of the composition of the optical recording material, any method of placing or depositing the optical recording material onto a substrate can be utilized.SELECTED DRAWING: Figure 11

The invention relates to an optical monomer and a preparation method and application thereof, the structural general formula of the optical monomer is as follows: R1, R2 and R3 are respectively selected from one of hydrogen and C1-C4 alkyl, A1 is selected from one of hydrogen and C1-C4 alkyl, and A2 is C1-C4 alkyl; r4 is selected from one of H, phenyl and C1-C4 alkyl, and A2 is C1-C4 alkyl; and R5 is hydrogen or methyl. The optical monomer provided by the invention contains a (methyl) acrylate group, and has the properties of high refractive index and low volume shrinkage; and a plurality of aromatic rings with high molar refractive index and low molar volume are contained, so that the whole molecule of the whole monomer is extremely high in refractive index. The monomer structure provided by the invention has a plurality of branched chains, the overall molecular weight is small, and the molecules are not easy to agglomerate.

The invention provides a four-port single-mode grating filter combined with a semi-symmetric fano resonance structure, and relates to the field of optical communication and optical sensing, and the filter comprises an F-P cavity and two bending coupling waveguides which are symmetrical up and down; the F-P cavity is arranged between the two bent coupling waveguides; the Bragg grating comprises a central waveguide, a conical grating and a Bragg grating; and two small circular holes are formed in each bent coupling waveguide. According to the technical scheme of the invention, two circular small holes are designed in each of the upper and lower bent waveguides to construct a semi-symmetric Fano resonant structure, and the two groups of circular small holes are in central symmetry. By constructing a semi-symmetric Fano resonant structure, the transmission efficiency of the drop end on the four-port single-mode grating filter is improved.

The invention discloses a photovoltaic ecological system based on a holographic frequency division technology. The photovoltaic ecological system comprises a frame body; the frequency-division concentrating photovoltaic unit comprises a substrate layer which is formed by connecting a heat conducting plate and a dodging plate and is connected with the frame body through a reciprocating motion mechanism, a concentrating layer and a holographic grating layer which are sequentially arranged above the heat conducting plate, and a photoelectric conversion battery arranged on the heat conducting plate; the light adjusting unit is arranged between the two adjacent frequency division concentrating photovoltaic units and comprises two frequency division plates connected through a rotating pair, and the ends, away from each other, of the two frequency division plates are connected with the corresponding frequency division concentrating photovoltaic units through rotating pairs; the reflective optical baffles are arranged on the two sides of the substrate layer, and side wall batteries are further arranged on the sides, close to the light adjusting units, of the reflective optical baffles. According to the invention, through a spectrum frequency division and space light energy distribution mechanism, multi-band efficient utilization of sunlight is realized, the light quality and the light quantity required by plant photosynthesis are guaranteed, and the photovoltaic power generation efficiency is improved.

Embodiments of the present disclosure provide methods for forming optical device structures. An exemplary method generally includes disposing a first material device layer on a substrate; patterning a portion of the first material device layer to form a first plurality of device structures in the first material device layer; disposing a second material device layer on an unpatterned portion of the first device material layer; performing a nanoimprint lithography process on the second material device layer to form a second plurality of device structures on the first material device layer; and disposing a metal coating on the second plurality of device structures.

The invention provides a volume holographic grating exposure parameter determination method and a two-dimensional pupil expansion volume holographic optical waveguide, and the method comprises the steps: carrying out the multiple rotation of a vector of a first light beam, a vector of a second light beam and a holographic photosensitive material when the wavelengths of the first light beam and the second light beam are first recording wavelengths, the rotated vectors of the first light beam and the second light beam and the rotated material position of the holographic photosensitive material are obtained; converting the wavelengths of the first light beam and the second light beam into a second recording wavelength, and rotating the rotated vectors of the first light beam and the second light beam at least once to obtain in-material vectors of the first light beam and the second light beam; determining the in-air vectors of the first light beam and the second light beam according to the in-material vectors of the first light beam and the second light beam; and determining incident angles of the first light beam and the second light beam according to the in-air vectors of the first light beam and the second light beam. According to the method, the manufacturing efficiency of the two-dimensional pupil-expanding body holographic optical waveguide comprising the coupling-in, turning and coupling-out body holographic grating can be improved.

The invention relates to a waveguide grating, in particular to a method for manufacturing a waveguide grating with continuous gradually-changing groove depth, which comprises the following steps of: accurately measuring and calibrating ion beam current density distribution of a used ion beam in a working plane; establishing a cooperative control model associated with a target groove depth curve, ion beam current density distribution and scanning speed, associating the etching depth with the ion beam total dose, and accurately controlling the ion beam total dose received by each point on the waveguide grating by dynamically regulating and controlling the scanning speed of the substrate relative to the ion beam, so as to realize accurate control of the etching depth. The accurate control on the groove depth distribution is realized; based on the cooperative control model, the scanning speed corresponding to the target groove depth curve is solved by combining the set target groove depth curve and the calibrated ion beam current density distribution; and performing ion beam etching based on the solved scanning speed, and finally forming a continuous gradual change groove depth accurately corresponding to the target groove depth curve on the waveguide grating. The method can effectively overcome the defect that the high-precision waveguide grating with the continuous gradually-changing groove depth is difficult to manufacture.

Methods, apparatus, devices, and systems for displaying three-dimensional objects by individually diffracting different colors of light are provided. In one aspect, an optical device includes: a first optically diffractive component including a first diffractive structure configured to diffract a first color of light having a first incident angle at a first diffracted angle, a second optically diffractive component including a second diffractive structure configured to diffract a second color of light having a second incident angle at a second diffracted angle, a first reflective layer configured to totally reflect the first color of light having the first incident angle and transmit the second color of light, and a second reflective layer configured to totally reflect the second color of light having the second incident angle. The first reflective layer is between the first and second diffractive structures, and the second diffractive structure is between the first and second reflective layers.

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 lamina 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.

The invention discloses a nano-pillar array NaKSb photoelectric cathode for enhancing light absorption, which is characterized in that through the design of a double-layer TiOtwo-dimensional nano grating and a nano-pillar array structured NaKSb photoelectric cathode layer, the optical path of light with the wave band of 450-900 nm in the photoelectric cathode is increased under the condition that the thickness of the NaKSb photoelectric cathode is not increased, the reflectivity of the wave band of 400-600 nm is reduced, and the light absorption of the NaKSb photoelectric cathode is enhanced. The absorption rate at 400-1000 nm is improved by 32.28% compared with that of a traditional planar film type photoelectric cathode, the absorption rate at 800-1000 nm near-infrared band is improved by 40.27% compared with that of the traditional planar film type photoelectric cathode, the problem that the absorption of the traditional planar film type photoelectric cathode near-infrared band is insufficient is solved, and the photoelectric cathode is suitable for high-performance low-light night vision imaging devices.

A variable magnification optical system consists of, in order from an object side, a front group, an intermediate group, and a subsequent group. The front group consists of two or fewer lens groups having a positive refractive power. The intermediate group consists of two or fewer lens groups having a negative refractive power. The subsequent group consists of a plurality of lens groups. A lens group of the subsequent group closest to the object side is a first subsequent lens group having a positive refractive power. Two or fewer focusing groups that move along an optical axis during focusing are disposed in the subsequent group. During magnification change, a lens group of the front group closest to the object side is fixed with respect to an image plane.

Provided are: an optical laminate which contains a plurality of liquid crystal layers in which liquid crystal compounds are oriented in different states, and which has a low reflectivity of a regular reflection component when light is incident thereon; a display device; and a sensor. The optical laminate includes a first liquid crystal layer containing a liquid crystal compound and a second liquid crystal layer containing a liquid crystal compound, the first liquid crystal layer is adjacent to the second liquid crystal layer, and the first liquid crystal layer has a liquid crystal alignment pattern which changes while continuously rotating in at least one in-plane direction from the optical axis of the liquid crystal compound. The optical laminate satisfies predetermined requirements.

The present invention relates to a transmission grating and a preparation method therefor. The transmission grating comprises: a substrate, which has a first surface; a grating layer, which comprises trapezoidal grating teeth arranged in an array on the first surface, wherein the grating teeth extend in the direction of thickness of the substrate, and a gap is provided between two adjacent grating teeth; and a dielectric layer, which is arranged on a surface of the grating layer and fills the gaps, wherein the dielectric layer has a second surface on the side thereof away from the substrate; there is a difference between the height of the grating teeth and the distance between the second surface and the first surface, the difference being m; and incident light passes through the interior of the grating layer and is incident towards the second surface. By means of the design of a film layer structure and film layer dimensions of the transmission grating, the present invention can acquire transmission gratings having different diffraction efficiencies and polarization degrees, and can accurately control the dimensions of the film layer structure of the transmission grating during machining, thereby facilitating machining.

A light-receiving device includes a light-receiving element in which a plurality of light-receiving portions are provided; and a glass cover that has a first surface and a second surface opposite to the first surface and that is fixed above the light-receiving element such that the second surface faces the light-receiving element. The glass cover includes a plurality of diffraction gratings provided in at least one of the first surface and an inside of the glass cover. Each of the plurality of diffraction gratings is configured to concentrate laser light for distance measurement on each of the plurality of light-receiving portions, the laser light for distance measurement incident on the first surface of the glass cover.

The invention provides a polymerizable monomer with the refractive index larger than 1.7 and a preparation method and application thereof.The polymerizable monomer has the structure shown in the formula G1 or G2 or G3 or G4 or G5 or G6, the refractive index of the polymerizable monomer is 1.7 or above, and therefore a holographic recording medium has various excellent characteristics such as high sensitivity, high diffraction efficiency and high refractive index modulation degree; the holographic recording medium is used for a holographic grating, so that the holographic grating has high diffraction efficiency and high refractive index modulation degree.

An optical system is presented for use in a near-eye mixed reality system. The system comprises a relay system defining an eyebox of the optical system, said relay system being configured and operable to relay a virtual image light field from a light-engine onto an eye pupil plane while combining said virtual image with real-world light field. The relay system is configured as a free space relay system configured for free space propagation of said virtual image light field being relayed, said free space relay system comprising at least one off-axis 4f-system. Each of said at least one off-axis 4f-system comprises at least one lens formed from at least one resonance-domain surface relief diffractive optical element (SRDOE) operable for combining said virtual image light field with the real-world light field, said at least one SRDOE being configured with a predetermined global surface relief pattern characterized by global variation of at least some of pattern parameters across said SRDOE.

To provide a zoom lens which is compact and compatible with a large-format sensor, and has a high zoom ratio.SOLUTION: A zoom lens disclosed herein consists of a first lens group U1 with positive refractive power configured to be stationary for zooming, multiple intermediate lens groups including a lens group U2 with negative refractive power and two lens groups U3, U4 with positive refractive power, both being configured to move for zooming, and a final lens group U5 located on the most image side and configured to be stationary for zooming. The first lens group includes at least five positive lenses. A composite imaging magnification βzt of all lens groups included in the intermediate lens groups at the telephoto end, and an imaging magnification βrw of the final lens group at the wide-angle end satisfy conditions expressed as: 2.1≤βzt≤4.0, and 1.5≤βrw≤2.1.SELECTED DRAWING: Figure 1

Improvements to gratings for use in waveguides and methods of producing them are described herein. Deep surface relief gratings (SRGs) may offer many advantages over conventional SRGs and Bragg gratings, an important one being a higher S -diffraction efficiency. In one embodiment, deep SRGs can be implemented as polymer surface relief gratings or evacuated Bragg gratings (EBGs). EBGs can be formed by first recording a holographic polymer dispersed liquid crystal (HPDLC) grating. Removing the liquid crystal from the cured grating provides a polymer surface relief grating. Polymer surface relief gratings have many applications including for use in waveguide-based displays.

The eyepiece waveguide stack includes a first eyepiece waveguide including a first incoupling diffractive optical element and a first compound pupil dilator, and a second eyepiece waveguide including a second incoupling diffractive optical element and a second compound pupil dilator, the second incoupling diffractive optical element being laterally offset from the first incoupling diffractive optical element.

The embodiment of the invention provides a diffractive optical structure and near-to-eye display equipment. The diffractive optical structure comprises a waveguide substrate and a grating area and a non-grating area which are arranged on the waveguide substrate, a grating structure is formed in the grating area, a dielectric layer covers the non-grating area, and the refractive indexes of the grating structure and the dielectric layer are n1; a pre-compensation structure is arranged in at least part of areas, corresponding to the multiple grating structures and / or the multiple non-grating areas, on the waveguide substrate, the pre-compensation structure is a concave structure which is formed in the thickness direction of the waveguide substrate and has a specific depth, and the concave depth hi of the pre-compensation structure meets the condition that hi is smaller than di * (n1 / n2), wherein di is the grating depth of the grating structure or the thickness of the dielectric layer at the position corresponding to the pre-compensation structure, i is the number of the grating area or the non-grating area, and i is a positive integer greater than or equal to 1; n2 is the refractive index of the waveguide substrate.

The invention relates to a bottom alignment grating preparation method and a bottom alignment grating, and the bottom alignment grating preparation method comprises the steps: depositing a grating material on a light-transmitting substrate, so as to form a grating material layer on the light-transmitting substrate; etching the grating material layer to form a plurality of grating areas with different heights on the grating material layer; and respectively etching each grating area to the light-transmitting substrate to form a plurality of groups of gratings with different heights so as to obtain a bottom-aligned grating. The partition structure of each grating area of the bottom-aligned grating is bottom-aligned, so that the optical efficiency of an optical device can be improved, and an optical film interference effect caused by a residual film is reduced. The bottom alignment grating can be prepared through the preparation method of the bottom alignment grating provided by the invention.

The invention discloses a U-shaped groove grating ion beam etching method based on a mask shadow effect, and relates to the technical field of U-shaped groove etching, and the method comprises the steps: placing a substrate with a photoresist grating mask in an inclined manner, and enabling an ion beam to bombard the photoresist grating mask in an inclined incidence manner; through a shadow effect generated by a photoresist grating mask on an ion beam, the etching dose distribution of different areas on the surface of a substrate is regulated and controlled, so that the etching dose of the central area of the groove bottom is greater than that of the areas on the two sides, and the U-shaped groove with a smooth and gradually-changed bottom contour is directly etched and formed. By constructing the smooth transition U-shaped groove bottom structure, sharp edges and corners are thoroughly eliminated, and the phenomenon of electric field concentration is remarkably relieved, so that the damage risk under high-power laser irradiation is effectively reduced, the stability of the grating in an extreme environment is improved, and the service life of the grating in the extreme environment is prolonged.

The invention discloses a femtosecond laser direct-writing Type X structure-based geometric phase fork-shaped grating, a preparation method and application of the femtosecond laser direct-writing Type X structure-based geometric phase fork-shaped grating in vortex light, and belongs to the technical field of laser processing, and the femtosecond laser direct-writing Type X structure-based geometric phase fork-shaped grating comprises design and parameter calculation of a geometric phase fork-shaped grating device, determination of a processing parameter window of a Type X structure and the femtosecond laser direct-writing fork-shaped grating. According to the invention, femtosecond laser is utilized to induce and generate an anisotropic nanopore structure with ultra-high transmittance higher than 97% in fused quartz and other transparent materials, namely a Type X structure, the structure has a birefringence characteristic, and the slow axis angle of the structure is always perpendicular to the laser polarization direction, so that the slow axis angle can be continuously adjusted by adjusting laser polarization. The Type X structure serves as a metasurface unit of the geometric phase fork-shaped grating, geometric phase regulation and control are achieved by controlling slow axis orientation of the Type X structure, and therefore generation and regulation and control of vortex light are achieved. The method is high in efficiency and simple in process.