575 results about "Diffraction efficiency" patented technology

The invention discloses a holographic sight based on a volume Bragg grating, and belongs to the field of holographic optics. The holographic sight comprises a sight housing, a semiconductor laser, a wave-locking element, a beam expander, an off-axis parabolic reflector and a holographic grating. The wave-locking element is a reflective volume Bragg grating, and the holographic grating is a transmissive volume Bragg grating. Both have excellent selectivity for the wavelength and incident angle of light. At the same time, both are made of photothermorefractive glass, which is less affected by the external temperature and can effectively reduce the deviation of the output wavelength, thereby reducing the deviation of the holographic grating mark image and increasing the accuracy and stability of the holographic sight. The photothermorefractive glass has a high refractive index modulation degree, which achieves a higher holographic diffraction efficiency, making the displayed holographic image brighter and more recognizable. In addition, the components of the beam expander and the off-axis parabolic reflector are used to shorten the optical path and reduce the overall structural size of the sight.

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 discloses an optimization method of an optical diffraction neural network, which is characterized in that a multi-target loss function is designed in combination with classification reasoning performance and diffraction efficiency performance, and diffraction layer phase parameter distribution of the optical neural network is jointly optimized, so that the diffraction efficiency of the trained optical diffraction neural network is greatly improved. Compared with a traditional cross entropy loss function training method, the method has the advantages that the loss function of the diffraction efficiency performance is added on the basis of the cross entropy loss function of the original classification performance, and the diffraction efficiency of the optical diffraction neural network is greatly improved. The trained optical diffraction neural network alleviates the problem of spurious distribution of an output plane field, has high signal contrast, enhances the robustness of the system, and further promotes the application of the optical diffraction neural network in an actual image classification scene.

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.

Gradient encapsulation of waveguide outcoupler gratings for control of diffraction efficiency and directionality includes a first grating formed over a substrate, the first grating having a plurality of first structures extending away from the substrate, the first grating corresponding to an outcoupler. The device includes a first encapsulant disposed in one or more gaps formed between adjacent first structures, where a fill ratio of the first encapsulant decreases along the first grating. Also described herein are methods for fabricating the device.

Methods, apparatus, devices, subsystems, and systems for holographically displaying three-dimensional objects are provided. In one aspect, an optical device includes: an optical guiding device configured to guide light to propagate along a first direction within the optical guiding device; an in-coupling diffractive structure configured to diffract the light to propagate in the optical guiding device; and out-coupling diffractive structures configured to diffract at least part of the light out of the optical guiding device along a second direction different from the first direction. The out-coupling diffractive structures are configured to have gradually increased diffraction efficiencies for the light along the first direction away from the in-coupling diffractive structure. A first diffraction efficiency of the in-coupling diffractive structure is no smaller than a first threshold, and a second diffraction efficiency of each out-coupling diffractive structure is no greater than a second threshold that is no greater than the first threshold.

The invention provides a grating assembly and a manufacturing method of the grating assembly. The grating assembly comprises a substrate; the number of the optical cement auxiliary structures is multiple, and the multiple optical cement auxiliary structures are formed on the surface of one side of the substrate at intervals through nanoimprint; the functional layer covers the sides, away from the substrate, of the optical cement auxiliary structures in a shape follow-up mode so that the side faces and the top faces of the optical cement auxiliary structures can be wrapped by the functional layer, and gaps are reserved in the sides, away from the substrate, of the functional layer; the optical adhesive layer is arranged on the side, away from the substrate, of the optical adhesive auxiliary structure, and the projection of the optical adhesive layer on the substrate completely covers the optical adhesive auxiliary structure and the functional layer; the functional layer is a deposition layer, the grating assembly further comprises a plurality of diffraction gratings, and the diffraction gratings are filled in the gaps. The problem that the diffraction efficiency of a grating assembly in the prior art is difficult to improve is solved.

The embodiment of the invention provides a grating structure, a light guide device and head-mounted display equipment. Wherein the grating structure comprises a plurality of grating units and filling materials, the grating units are periodically arranged at intervals, the space between the adjacent grating units is filled with the filling materials, and the filling materials cover the top surfaces of the grating units; wherein the grating unit has a first refractive index n1, the filling material has a second refractive index n2, and the grating structure meets the condition that the absolute value of the difference between n1 and n2 is smaller than or equal to 0.5. According to the grating structure provided by the embodiment of the invention, the diffraction efficiency of the diffraction behavior can be reduced through the new design of the grating structure, and rainbow lines are prevented from being formed in human eyes.

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.

The invention discloses a method for designing a myopia prevention and control lens based on harmonic diffraction. Relates to the technical field of eye vision optics, in particular to the technical field of a myopia prevention and control lens design method based on harmonic diffraction. According to the method, a harmonic diffractive optical lens chromatic aberration correction method and a harmonic diffractive optical lens diffraction efficiency calculation method when shielding is considered are firstly designed, chromatic aberration is effectively eliminated, the diffraction efficiency is evaluated, and then influences of chromatic aberration correction and shielding error manufacturing are balanced by designing a balance optimization model. The method comprises the following steps: designing a diffractive optical element on the refraction surface of a myopia prevention and control lens to obtain a refractive and diffractive optical lens; modulating the harmonic number # imgabs0 # of the refractive and diffractive optical lens to obtain a harmonic diffractive optical lens; designing a chromatic aberration correction method of the harmonic diffractive optical lens; harmonic diffractive optical lenses are designed that take into account additional refractive power and diffraction efficiency at the time of manufacturing shields.

The embodiment of the invention discloses a diffractive optical structure, a method for regulating and controlling the diffraction efficiency of a non-coupling-in region and optical equipment. The diffractive optical structure comprises a substrate, and at least one coupling-in region and at least one coupling-out region which are arranged on the substrate; wherein the coupling-in area is used for coupling external light rays into the substrate, and the coupling-out area is used for performing pupil expansion on the light rays and coupling out the light rays; the coupling-out area is provided with a coupling-out grating with a residual layer, and the residual layer has a set thickness change trend at different positions of the coupling-out grating so as to regulate and control the coupling-out intensity of light; the refractive indexes of the residual layer and the substrate are different, the refractive index difference between the residual layer and the substrate is n, and n is larger than or equal to 0.1 and smaller than or equal to 0.8; the coupling-out area is configured to regulate and control the diffraction efficiency curve peak position of the coupling-out grating through the thickness change trend of the residual layer in the process that light is transmitted in the length direction of the diffractive optical structure.

The invention discloses a thiophene monomer, a holographic recording medium, a preparation method and a related device, the structural general formula of the thiophene monomer is shown in the specification, the refractive index of the monomer is larger than 1.8 and smaller than 1.9, the diffraction efficiency can be remarkably improved, the thiophene monomer is applied to preparation of a photopolymer type holographic recording medium, and the photopolymer type holographic recording medium with the sensitivity larger than 100 cm / mJ can be obtained. According to the holographic recording medium, the diffraction efficiency of the recording grating is larger than 95%, the refractive index modulation degree is larger than 0.1, and the shrinkage rate is lower than 1%, and further, the holographic recording medium can be used for preparing a volume holographic grating, a holographic optical element and an optical device.

The invention discloses a (methyl) acrylate monomer, a holographic recording medium, a preparation method and a related device.The structural formula of the (methyl) acrylate monomer is as shown in G1-G19. The preparation method is easy to operate and high in synthesis yield, and further, the holographic recording medium can be applied to holographic recording. According to the photopolymer holographic recording medium, the (methyl) acrylate monomer with the structure is introduced into the photopolymer holographic recording medium, so that the holographic recording medium with high sensitivity, high diffraction efficiency and no yellowing is obtained, and the invention further provides a preparation method of the holographic recording medium. The invention also provides a volume holographic grating, a holographic optical element and an optical device comprising the holographic recording medium.

The invention discloses a thianthrene monomer, a holographic recording medium, a preparation method and a related device, the structural formula of the thianthrene monomer is shown as G1-G6, the refractive index of the thianthrene monomer is larger than 1.7 and smaller than 1.8, the diffraction efficiency can be remarkably improved, and further, the holographic recording medium can be applied to holographic recording. The thianthrene monomer with the structure is introduced into the photopolymer type holographic recording medium, so that the holographic recording medium with high sensitivity, high diffraction efficiency and high refractive index is obtained, and the invention further provides a preparation method of the holographic recording medium. The invention also provides a volume holographic grating, a holographic optical element and an optical device comprising the holographic recording medium.

The invention discloses a (methyl) acrylate monomer, a holographic recording medium, a preparation method and a related device.The structural formula of the (methyl) acrylate monomer is as shown in G1-G5. The preparation method is easy to operate and high in synthesis yield, and further, the holographic recording medium can be applied to holographic recording. The (methyl) acrylate monomer with the structure is introduced into the photopolymer type holographic recording medium, reverse migration of a short polymer chain can be effectively inhibited, and therefore the holographic recording medium with high sensitivity and high diffraction efficiency is obtained, and the invention further provides a preparation method of the holographic recording medium. The invention also provides a volume holographic grating, a holographic optical element and an optical device comprising the holographic recording medium.

The invention relates to a laser radar on-chip integrated chip based on acousto-optic modulation, an on-chip acousto-optic scanning method and a laser radar system. A plurality of groups of interdigital transducers are arranged on the lithium niobate film, two groups of chirp IDTs respectively work at a low-frequency band and a high-frequency band, and sound waves at the low-frequency band correspondingly generate a relatively large Bragg deflection angle; and the high-frequency-band sound waves correspondingly generate a relatively small Bragg deflection angle. The two groups of IDTs work cooperatively, so that two-dimensional vector scanning of a dual-frequency broadband can be realized in a chip plane; the pair of focusing IDTs can form a focusing sound field in an action area, so that the light beam subjected to two-dimensional deflection is controllably deflected in the Z direction, and the chip is endowed with the three-dimensional scanning capability. The device is high in diffraction efficiency and low in power consumption; unification of large-range search and high-precision scanning is realized; z-axis deflection is realized by integrating a special focusing type interdigital transducer, a three-dimensional scanning function is realized on a monolithic integrated acousto-optic chip, and the structure is extremely compact.

The invention discloses an accelerated simulation method of a gradient period polarization holographic grating and a related device, and the method comprises the steps: carrying out the D (kin) calculation of the direction of predicted incident light after passing through a grating layer, multiplying a calculation result with the amplitude of the corresponding incident light, calculating the diffraction efficiency, and carrying out the acceleration simulation of the gradient period polarization holographic grating. Compared with a traditional simulation method using complete strict coupling wave calculation, the method has the advantages that the process operation of multiple integration, matrix multiplication and matrix inversion is reduced, and the simulation speed can be greatly accelerated.

The invention provides a volume holographic grating preparation method, a volume holographic grating, an optical waveguide and a display device, and the method comprises the steps: obtaining a to-be-exposed holographic material which comprises a thermosetting liquid crystal material; providing a liquid crystal box, and filling the liquid crystal box with the holographic material to be exposed; based on a preset light source, performing exposure treatment on the holographic material to be exposed in the liquid crystal box to obtain a grating to be treated; and applying a preset electric field to the to-be-processed grating and heating the to-be-processed grating to which the preset electric field is applied so as to cure the thermosetting liquid crystal molecules oriented by the preset electric field in the to-be-processed grating, thereby obtaining the volume holographic grating. According to the volume holographic grating, the arrangement state stability of the liquid crystal molecules of the volume holographic grating at a relatively high temperature can be improved, so that the diffraction efficiency of the volume holographic grating is ensured, and the optical performance degradation of the volume holographic grating in a high-temperature state is avoided.

According to the photopolymer system based on the fluorine-containing liquid crystal, the grating device and the preparation method of the grating device, the mixed liquid crystal containing the nematic liquid crystal and the fluorine-containing liquid crystal at the same time is adopted in the photopolymer system, and therefore the polarity and dielectric anisotropy of the mixed liquid crystal material are improved; the overall electro-optical performance, uniformity and stability of the photopolymer system are improved, so that a grating device prepared based on the photopolymer system has good optical characteristics of low haze while having relatively high diffraction efficiency. Specifically, fluorine-containing biphenyl liquid crystals, fluorine-containing alkyne liquid crystals and fluorine-containing difluoromethoxy liquid crystals of which the carbon atoms of flexible side chains are 2-5, and nematic liquid crystals of which the delta epsilon is not less than 10 are selected to jointly form mixed liquid crystals; and the balance and optimization between the diffraction efficiency and haze performance of the photopolymer system and the grating device prepared from the photopolymer system are realized.

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.

The invention provides a blazed grating manufacturing method, which comprises the following steps: providing a substrate, covering the substrate with periodically arranged masks, and etching the substrate by utilizing an incident angle and a rotation angle, taking the masks as a mask and utilizing an ion beam to form a blazed grating. The incident angle is the angle between the first projection of the ion beam on the plane where the normal of the substrate is located and the normal of the substrate, the rotation angle is the angle between the second projection of the ion beam on the plane where the surface of the substrate is located and the tangent line of the surface of the substrate, and the anti-blazing angle of the blazed grating is determined according to the incident angle and the rotation angle. Therefore, the shielding effect of the mask can be reduced by using the incident angle and the rotation angle, so that the purpose of controlling the angle of the anti-blazing angle is achieved, the angle of the anti-blazing angle is controllable, the angle of the anti-blazing angle is increased by controlling the incident angle and the rotation angle, and finally the diffraction efficiency of the blazed grating is improved.

The invention relates to the technical field of optical equipment, and discloses a diffraction optical waveguide module and an AR device. The diffractive optical waveguide module comprises a diffractive optical waveguide substrate, and a coupling-in grating region, a turning grating region and a coupling-out grating region which are sequentially arranged on the diffractive optical waveguide substrate along a first linear direction; the coupling-in grating region is arranged in the upper half region of the diffractive optical waveguide substrate and is close to the side edge of the upper end part of the turning grating region; wherein the turning grating area is a one-dimensional grating. According to the diffraction optical waveguide module, efficient pupil expansion and diffraction efficiency of the turning grating area are achieved, the lighting effect of the whole diffraction optical waveguide is improved, and therefore the problems of imaging definition, image brightness, rainbow lines and the like in the prior art are solved.

The invention provides a photosensitive glass ceramic with lower visible light absorption loss, which comprises the following components in molar percentage: cation components: 50-65% of Si < 4 + >; 25 to 38% of Na < + >; 2-6% of Zn < 2 + >; 3-9% of Al < 3 + >; 0.001 to 0.1% of Ag < + >; 0.001 to 0.08% of Ce < 4 + >; 0.02 to 0.2 percent of Sb < 3 + >; the negative ion component comprises 88 to 98 percent of O < 2->, 0.001 to 0.09 percent of Sn < 4 + > and 88 to 98 percent of Sn < 4 + >; f-: 2 to 10%; and 0.05 to 2 percent of Br <->. Through reasonable component design, the obtained photosensitive microcrystalline glass is low in visible light absorption loss and can be used for preparing glass elements such as volume Bragg gratings with low optical loss and high diffraction efficiency.

The invention discloses a dendritic (methyl) acrylate monomer, a holographic recording medium, a preparation method and a related device. Wherein the structural formula of the dendritic (methyl) acrylate monomer is shown as G1-G12, the preparation method of the dendritic (methyl) acrylate monomer is simple and easy to operate, and further, the dendritic (methyl) acrylate monomer with the structure is introduced into the photopolymer type holographic recording medium, so that the photopolymer type holographic recording medium is prepared. The invention further provides a preparation method of the holographic recording medium, a volume holographic grating containing the holographic recording medium, a holographic optical element containing the holographic recording medium and an optical device containing the holographic recording medium.

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.

The invention discloses a 4, 4 '-bis (omega-alkenyl thioether) diphenyl sulfide monomer and a preparation method, the structural general formula of the 4, 4'-bis (omega-alkenyl thioether) diphenyl sulfide monomer is shown in the specification, n represents the number of methylene and is a positive integer, n = 1-10, the refractive index of a polymer obtained after the monomer and 4 '4-dimercapto diphenyl sulfide are polymerized is larger than 1.65 and smaller than 1.8, diffraction efficiency is remarkably improved, the preparation method is easy to operate, and the preparation method is suitable for industrial production. The invention further provides a photopolymer type holographic recording medium containing the monomer and a preparation method of the photopolymer type holographic recording medium, the sensitivity of the holographic recording medium is larger than 100 cm / mJ, the diffraction efficiency of a recording grating is larger than 95%, the refractive index modulation degree is larger than 0.1, the shrinkage rate is lower than 1%, and the preparation method is simple, controllable and suitable for industrial production. The invention also provides a volume holographic grating containing the holographic recording medium, a holographic optical element and an optical device.

Provided are an optical waveguide structure, an Augmented Reality (AR) device, and a method for obtaining an emergent light efficiency of an optical waveguide structure, which relates to the technical field of display. The optical waveguide structure includes: an optical waveguide body, a coupling-in grating disposed at the optical waveguide body, and a plurality of coupling-out gratings distributed and arranged. The coupling-in grating is configured to couple image light into the optical waveguide body. The optical waveguide body is configured to generate a total internal reflection of the image light to the coupling-out gratings. Diffraction efficiencies of each of the coupling-out gratings are different, and each of the coupling-out gratings is configured to couple the image light out of the optical waveguide body at the same brightness.

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, an important one being a higher S-diffraction efficiency. In one embodiment, deep SRGs can be implemented as polymer surface relief gratings or evacuated periodic structures (EPSs). EPSs can be formed by first recording a holographic polymer dispersed liquid crystal (HPDLC) periodic structure. Removing the liquid crystal from the cured periodic structure provides a polymer surface relief grating. Polymer surface relief gratings have many applications including for use in waveguide-based displays.

The invention discloses a dithiocarbamate monomer, a holographic recording medium, a preparation method and a related device, the structural general formula of the monomer is as shown in G1 and G2, R1 represents any one of hydrogen, halogen and C1-C4 alkyl, R3 represents any one of hydrogen, halogen and C1-C4 alkyl, A1 represents C1-C4 alkyl, A2 represents hydrogen or methyl, n is a positive integer, and n = 1-10. The dithiocarbamate monomer provided by the invention has high refractive index, and the holographic recording medium with high sensitivity, high diffraction efficiency and high refractive index modulation degree can be obtained by applying the dithiocarbamate monomer to preparation of the photopolymer holographic recording medium; holographic recording media can be used to prepare volume holographic gratings, holographic optical elements, and optical devices.

The application relates to a kind of diffractive optical element beam shaping methods based on spatial frequency filtering, obtain incident light beam, based on the homogenization light beam of preset, obtain corresponding geometric analytical phase distribution;Adjust the homogenization light beam to rectangular flat-top light beam, the phase correction processing of obtained geometric analytical phase;Based on spatial frequency filtering method processing the geometric analytical phase after phase correction, get the light field regulation and control distribution requirement after processing, the light field regulation and control distribution requirement after processing has phase and amplitude regulation and control requirement simultaneously;Design diffractive optical element, make it realize the light field regulation and control distribution requirement required, and utilize the diffractive optical element to realize the incident light beam shaping as the rectangular flat-top light beam.The application can realize the light beam homogenization effect of high uniformity, edge sharp and high diffraction efficiency, and obtain wide application prospect in laser welding, photoetching and biomedical and other aspects.