992 results about "Diffraction grating" patented technology

Head-mounted displays with waveguides comprising superimposed diffractive gratings and methods for fabricating said waveguides are described herein. In an embodiment, a head-mounted display comprises an optical element and an image source that provides an image beam to an optical element. The optical element comprises two gratings superimposed over each other, at least one of which comprising a buried diffractive grating. The buried diffractive grating comprises a high-refractive index material interspersed with a low-refractive index material or non-solid pockets, such as gas, air or vacuum. Light diffracted by a first of the two gratings is further diffracted by a second of the two gratings without interacting with a surface of the optical element between diffractions.

The invention relates to an all-fiber sub-hundred femtosecond laser based on an SESAM. The all-fiber sub-hundred femtosecond laser comprises the SESAM, a wavelength division multiplexer, a pumping source, a pumping protector, a gain fiber, a chirp fiber bragg grating, an isolator, a reflector, a compression unit and an autocorrelator. According to the invention, the chirp fiber bragg grating with the dispersion amount of 0.115 ps / nm is adopted to compensate positive dispersion in the cavity, so that mode-locked pulse with the spectral width of 23nm is realized. A transmission-type diffraction grating pair is adopted, the pulse width is compressed to 88fs, and the maximum spectral width 27nm is obtained under the dispersion of 0.00087 ps2 in a near-zero cavity. The condition that the optimal spectral bandwidth of the optimal seed source pulse based on the optical fiber chirped pulse amplification laser should be larger than 15 nm is met, and the compression pulse distortion of the amplifier is reduced. By adopting the linear cavity, the SESAM is adhered to the surface of the single-mode optical fiber patch cord for starting mode locking, so that an all-optical-fiber structure of the system is realized, and the single-mode optical fiber patch cord is suitable for industrial integrated application.

The invention relates to a design method of a star magnitude large dynamic range spectrum modulation system. The design method comprises the following steps: S1, adopting a cylindrical collimation beam expanding system, a star magnitude large dynamic range light splitting system and a DMD device; the star magnitude large dynamic range light splitting system is composed of a large dynamic light splitting optical system and an energy modulation optical system. The star isometric large dynamic light splitting optical system is composed of a steering reflecting mirror, a grating and an imaging reflecting mirror. The energy modulation optical system is composed of a steering mirror, a grating and a plane mirror. S2, selecting a DMD device and a grating; and S3, carrying out optimization design on the cylindrical collimation beam expanding system and the star magnitude large dynamic range beam splitting system. According to the invention, the cylindrical collimation and beam expanding system is adopted to replace a physical slit and a collimating mirror in the Czerny-Turner type plane diffraction grating optical structure, so that the imaging quality of the large-dynamic-range spectrum modulation optical system can be improved; and the problem of contradiction between the slit and the imaging quality in the initial structure can be solved.

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 laser module includes a QCL element, a MEMS diffraction grating, a lens holder holding a lens disposed between the QCL element and the MEMS diffraction grating, a package, an electrode terminal disposed along an inner wall surface of the package, and a wire for electrically connecting the electrode terminal and a coil. The top wall of the package faces the bottom wall of the package in a direction orthogonal to the optical axis direction of the lens. The MEMS diffraction grating includes an electrode pad electrically connected to the coil. The electrode pad is connected to the electrode terminal via the wire. A height position of the electrode pad with respect to the bottom wall is equal to or higher than a height position of the electrode terminal with respect to the bottom wall.

A semiconductor optical integrated element (11) according to the present invention comprises a DFB laser (12), an EA modulator (13), a bent waveguide (162), and an SOA (14) in the stated order on a substrate and further comprises an optical monitor (15) which is disposed on substantially the same axis as an optical axis (18) of emitted light of the DFB laser and into which leakage light from the bent waveguide enters. Also, a region (125) not including a diffraction grating may be disposed in a vicinity of one end of the DFB laser.　The present invention can thereby provide a semiconductor optical integrated element capable of suppressing degradation of integrated elements and controlling the integrated elements.

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 invention discloses a grating displacement encoder grating spacing error in-situ detection and self-compensation method, and belongs to the technical field of optical measurement, and the method comprises the steps: generating elliptically polarized light, modulating the elliptically polarized light into S polarized light, reflecting the S polarized light through a polarization beam splitter, converting the S polarized light into circularly polarized light through a quarter-wave plate, and enabling the circularly polarized light to enter a diffraction grating ruler; the diffraction grating ruler diffracts incident light to form first-order diffraction light and second-order diffraction light; processing and interference detection are carried out on the first-order diffraction light, and precise displacement conversion is carried out in combination with the Doppler effect of grating displacement; constructing an auto-collimation angle detection sensing module by using second-order diffraction light, and converting the distance manufacturing deviation of diffraction gratings by detecting the tiny change of a diffraction angle; and compensating the displacement measurement error of the grating encoder in real time according to the real-time detection result of the grating spacing manufacturing deviation. According to the invention, the off-line detection time and cost of the grating are greatly saved.

The invention provides a fiber optic spectrometer and a spectrum detection method, and belongs to the technical field of spectrum detection. The optical fiber spectrometer comprises an optical splitter and a detector, wherein the optical splitter comprises a multimode optical fiber and a diffraction grating which is formed by writing on the end face of the emergent end of the multimode optical fiber and is arranged opposite to the light sensing surface of the detector. The spectrum detection method comprises the following steps: calibrating a fiber optic spectrometer by using a tunable laser to obtain an initial transmission matrix for representing response characteristics of the fiber optic spectrometer under different wavelengths; correcting the initial transmission matrix by adopting a singular value decomposition algorithm to obtain a final transmission matrix; measuring a to-be-measured light source by using a fiber optic spectrometer to obtain a to-be-measured diffraction image; and reconstructing the spectrum of the to-be-measured light source according to the to-be-measured diffraction image and the final transmission matrix. According to the invention, the diffraction image of the light source to be detected is measured by means of the optical fiber spectrometer with a simple structure, and the spectrum of the light source to be detected can be rapidly and reliably detected in combination with the transmission matrix obtained by calibrating the optical fiber spectrometer.

An optical displacement sensor comprises a reflective surface and one or more diffraction gratings which, together with the reflective surface, each define a respective interferometric arrangement. The reflective surface is moveable relative to the diffraction grating(s) or vice versa. Light from a light source propagates via the interferometric arrangement(s) to produce an interference pattern at a respective set of photo detectors. Each interference pattern depends on the separation between the reflective surface and the respective grating. A collimating optical arrangement at least partially collimates the light between the light source and the diffraction grating(s). For the or each interferometric arrangement, when the reflective surface or the diffraction grating is in a zero-displacement position, the optical path length L of the light propagating between the diffraction grating and the reflective surface satisfies the relationship:L=Tz⁢n2,to within 20% ofTz2,where n is an integer; where Tz is the Talbot length, defined by:Tz=λ1-1-λ2p2,where λ is the wavelength of the light, and where p is the grating period of the respective diffraction grating.

The invention relates to a pulse compressor, in particular to a pulse compressor convenient to adjust, which comprises a collimating lens, a first plane reflecting mirror, a first diffraction grating, an angle reflecting mirror, a high-low mirror and a second plane reflecting mirror, the first plane mirror is fixedly installed on the precision rotating table, and the angle mirror is fixedly installed on the precision displacement table. According to the technical scheme provided by the invention, the defects in the prior art that different pulse width compression amounts are inconvenient to obtain by changing the relative interval of the grating and adjusting the introduced negative dispersion value through the diffraction angle of the grating, and collimation adjustment of the incident light is inconvenient can be effectively overcome.

Provided is an optical transmitter having high manufacturing stability and a high reflection suppression effect. In the optical transmitter, a distributed feedback (DFB) laser having an active region formed as a multiple quantum well that generates an optical gain by current injection and a diffraction grating, an electro-absorption (EA) modulator having an absorption region formed as a multiple quantum well having a composition different from a composition of the DFB laser, a semiconductor amplifier (SOA) having an active region having a same composition as the composition of the DFB laser, a bent waveguide that rotates a light propagation direction by an angle θwg, and a passive waveguide connected to the SOA and including a core having a band gap wavelength shorter than an oscillation wavelength of the DFB laser are monolithically integrated on one substrate. The passive waveguide has a tapered region and a narrow waveguide region. The tapered region converts a width W1 of the passive waveguide connected to the SOA into a width W2 of the narrow waveguide region, and the passive waveguide forms the angle θwg with respect to a normal line to an end surface of the substrate and is in contact with the end surface of the substrate.

The utility model discloses a novel wavelength selection switch, which relates to the technical field of all-optical communication and comprises an optical fiber collimation array, a Fourier lens, a 4f imaging system, a diffraction grating, an LCOS (Liquid Crystal On Silicon) device and an MEMS (Micro Electro Mechanical System) device which are sequentially arranged along the direction of an optical path. According to the utility model, by utilizing the fine modulation and deflection characteristics of the LCOS device to the light beam and combining the wide-angle scanning characteristic of the MEMS device, the wavelength selective switch capable of greatly increasing the number of output ports is provided, the reconfigurable optical add-drop multiplexing function is realized, the miniaturization and standardization of the WSS module are realized, and the optical communication technology is high in efficiency and wide in universality.

A system and method are provided for determining a location of a laser using a diffraction grating. The system includes a lens that projects diffraction patterns from the diffraction grating as an image of diffraction peaks onto a plane. Optical sensors then sense the diffraction peaks. A processor connected to the optical sensors applies a laser position determination method to determine the laser location. In the method, the processor obtains the diffraction peak measurements from the optical sensors and applies a transform to arrange the diffraction peaks into a grid of regularly spaced peaks. The processor then applies convolution kernels to analyze the grid of regularized peaks to to determine a position of a zeroth order diffraction central peak that is used to calculate the angle of incidence of the axis of the laser beam to determine the laser position.

The optical system includes: a light guide for guiding an image light ray to a field of view region of a user as a virtual image. The light guide includes a diffraction structure region constituting a surface-relief diffraction grating dividing the image light ray propagating in a first propagation direction intersecting a thickness direction of a body into a plurality of image light rays propagating in a second propagation direction intersecting the first propagation direction, in the first propagation direction. The diffraction structure region includes a first diffraction structure, and a second diffraction structure on an opposite side of the first diffraction structure from an in-coupling region in the first propagation direction. A grating height of the first diffraction structure is greater than a grating height of the second diffraction structure. A grating width of the first diffraction structure is greater than a grating width of the second diffraction structure.

A vertical cavity light-emitting element includes a gallium-nitride-based semiconductor substrate, a first multilayer reflector, a semiconductor structure layer, a second multilayer reflector, and a current confinement structure. The first multilayer reflector is formed on the substrate. The second multilayer reflector is formed on the semiconductor structure layer and constitutes a resonator with the first multilayer reflector. The current confinement structure is formed between the first multilayer reflector and the second multilayer reflector to concentrate a current in one region of the active layer. A diffraction grating is formed in a region overlapping with the one region when viewed from a normal direction of an upper surface of the substrate. The diffraction grating is made of a plurality of slit structures parallel to each other.

Some disclosed examples involve controlling a light-steering system to direct light emitted by at least a first light source of a light source system to a first plurality of areas of a target object, wherein controlling the light-steering system involves controlling one or more adjustable micromirrors, one or more adjustable lenses, one or more adjustable diffraction gratings, or combinations thereof. Some examples involve receiving ultrasonic receiver signals from an ultrasonic receiver system corresponding to photoacoustic responses of the target object to light provided the light source system to each area of the first plurality of areas and determining a selected area of the target object from which additional ultrasonic receiver signals will be obtained, wherein determining the selected area involves detecting a blood vessel within the target object. Some examples involve controlling the light source system to obtain additional ultrasonic receiver signals from the selected area.

To provide a light receiving element for optical communication superior in polarization distinctiveness, wavelength separability, high-speed responsiveness, and thinning.SOLUTION: A light receiving element for optical communication comprises: a semiconductor layer or a dielectric layer; a semiconductor light absorption layer that is formed on the semiconductor layer or the dielectric layer; a short wavelength infrared transparent layer that is formed on the semiconductor light absorption layer; and a metal diffraction grating that is formed on the short wavelength infrared transparent layer. Short wavelength infrared light incident from an upper direction of the metal diffraction grating made incident, a period p of the metal diffraction grating is set so that a surface plasmon resonance wave is excited on a boundary surface between the metal diffraction grating and the short wavelength infrared transparent layer by the short wavelength infrared light. A thickness of the semiconductor light absorption layer is set so that the period p of the metal diffraction grating and a waveguide mode transmission wavelength β in which the three layers (the semiconductor layer or the dielectric layer, the semiconductor light absorption layer, and the short wavelength infrared transparent layer) are regarded as a clad core light waveguide path satisfy a condition of β=p*0.9 to 1.1.SELECTED DRAWING: Figure 1

An electronic device may include a waveguide that directs light to an eye box. The waveguide may include a diffractive grating structure. A projector may generate image light coupled into the waveguide by a first input coupler. A light source may generate supplemental light coupled into the waveguide by a second input coupler. The diffractive grating structure may couple the image light out of the waveguide within a central region of the field of view (FOV) of an eye box and may couple the supplemental light out of the waveguide at a location within a peripheral region of the FOV. The location may be outside of the central region by at least 10 degrees. A gaze tracking sensor may estimate a user's gaze direction at the eye box. A processor may wake or power down the projector responsive to the gaze direction overlapping the location for a predetermined time period.

The invention provides an anti-counterfeit label film coating tension control method and system, and relates to the technical field of film coating tension control. The method comprises the following steps: acquiring surface image data of a substrate film; identifying and acquiring real-time coordinates of the feature points; calculating the local strain of the substrate film according to the real-time coordinates of the feature points; calculating to obtain a strain deviation; calculating the time required by the film section corresponding to the strain deviation to reach the film coating station as the adjustment time; calculating a tension compensation amount according to the strain deviation; and within the adjusting time, the tension control unit adjusts the tension applied to the substrate film according to the tension compensation amount. According to the method, through accurate local strain measurement and prospective tension adjustment, it is ensured that each section of film is kept in an ideal strain state at the moment of film coating, so that the integrity and functional effectiveness of optical microstructures such as diffraction gratings are thoroughly protected, and the technical problems in anti-counterfeit label film coating production are effectively solved.

The invention relates to a hundred-milliwatt high-power high-repetition-frequency terahertz strong source generating device at room temperature, belongs to the technical field of nonlinear optical frequency conversion, and solves the problems that the terahertz conversion rate is low and additional cooling equipment is needed in the prior art. The beam expanding lens group is used for carrying out light spot beam expanding on the femtosecond pumping laser until the diameter of a light spot is twice of the original diameter; the plane mirror group is used for guiding the pump laser after beam expansion; the first half-wave plate, the reflective diffraction grating, the gold reflector and the third ultrafast reflector are used for adjusting polarization and diffraction reflection; the 4-f telescope imaging lens group is used for reducing the spot diameter of the received pump laser and imaging the pump laser to the lithium niobate crystal; the lithium niobate crystal generates terahertz pulse radiation in the direction perpendicular to the wavefront; the terahertz collection module receives and focuses the terahertz pulse radiation; and the measuring device is used for receiving the focused terahertz pulse radiation for measurement.

The invention discloses a single-side entrance pupil binocular waveguide and AR glasses, and relates to the technical field of augmented reality, and the waveguide specifically comprises a waveguide substrate which is divided into a first substrate and a second substrate along a central axis; the first substrate is provided with an entrance pupil region, a first turning region, a first exit pupil region and a second turning region, the second substrate is provided with a second exit pupil region and a third turning region, and the entrance pupil region, the first turning region, the second turning region, the third turning region, the first exit pupil region and the second exit pupil region all form diffraction gratings; incident light enters through the entrance pupil region, passes through the first transition region, the second transition region and the third transition region and then exits from the second exit pupil region, so that a first optical waveguide path is formed. Wherein the second turning area is used for transferring light rays emitted to the outline notch from the first turning area to the third turning area. By adopting the method and the device, the technical effect that the single-side entrance pupil binocular waveguide can display complete image information in the non-light-source-side eyes of the wearer is achieved.

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.

A weapon sight includes a chassis and an optical system. The chassis is coupleable to a firearm. The optical system is coupled to the chassis and includes a light source, a collimator, a mirror, a diffraction grating, and a hologram. The light source is a light emitting diode (LED) that emits light. The collimator receives the light from the light source and reflects the light in parallel rays. The folding mirror receives the light from the collimator and reflects the light in the parallel rays. The diffraction grating receives the light from the folding mirror and diffracts the light. The hologram receives the light from the diffraction grating to output a reticle visible by a user of the weapon sight.

A system and method are provided for characterizing a laser using a diffraction grating. The system includes a lens that projects diffraction patterns from the diffraction grating as an image of diffraction peaks onto a plane. Optical sensors then sense the diffraction peaks. A processor connected to the optical sensors applies the laser characterization method to determine the laser wavelength, irradiance and angle of incidence. In the method, the processor obtains the diffraction peak measurements from the optical sensors and applies a transform to arrange the diffraction peaks into a grid of regularly spaced peaks. The processor then applies convolution kernels to analyze the grid of regularized peaks to determine a wavelength, irradiance and angle of incidence of the laser.

An optical transmitter includes a distributed feedback (DFB) laser having an active region formed as a multiple quantum well (MQW) and a diffraction grating, an electro-absorption (EA) modulator having an absorption region formed as a MQW having a composition different from a composition of the DFB laser, a semiconductor amplifier (SOA) having an active region having a same composition as the composition of the DFB laser, a bent waveguide that rotates a light propagation direction, and a passive waveguide connected to the SOA and including a core having a band gap wavelength shorter than an oscillation wavelength of the DFB laser. A tapered region of the passive waveguide converts a width W1 of the passive waveguide connected to the SOA into a width W2 of a narrow waveguide region of the passive waveguide, and the passive waveguide is in contact with the end surface of the substrate.

The invention relates to the technical field of grating interferometry, in particular to a Littrow grating interferometry device and a use thereof. The device comprises: a two-frequency orthogonal polarization light source, a polarizing beam splitting prism, a reflection assembly, a detector, and a first diffraction grating and a second diffraction grating having identical parameters. The output light of the two-frequency orthogonal polarization light source is split by the polarizing beam splitting prism into horizontally polarizing measuring light which is transmitted and vertically polarizing measuring light which is reflected. The two beams of measuring light undergo diffraction twice between the first diffraction grating and the second diffraction grating, and finally the two beams of measuring light interfere with each other and are incident on the detector. Grating displacement is calculated according to the interference pattern. The invention achieves secondary diffraction under Littrow incidence, and improves the precision of displacement measurement.

Waveguide modification includes modifying waveguide combiners, output coupler, and pupil expander regions, which contain diffraction gratings, based on user and display characteristics during manufacturing. The diffraction grating is generally configured to combine received display light, representing an image for display, and directs the combined light to a location where the image can be comfortably viewed by the user. Because the desired location for the display can vary based on characteristics of the user, the diffraction grating is modified during manufacturing, such as by covering portions of the grating, to tailor the characteristics of the diffraction grating for a particular user or group of users.

The light-guide plate includes a substrate, an incidence diffraction grating that diffracts incident light, and an emission diffraction grating that emits light from the substrate, the light being diffracted by the incidence diffraction grating. The emission diffraction grating is formed of a recessed / projected pattern formed on a substrate surface, the recessed / projected pattern includes a first group of parallel straight lines and a second group of parallel straight lines intersecting the first group of parallel straight lines, and a pitch of the first group of parallel straight lines is equal to a pitch of the second group of parallel straight lines. A relationship between the pitch P of the first group of parallel straight lines and the second group of parallel straight lines and a pattern width W of the recessed / projected pattern is defined as W / P, which is 0.15 or more and 0.85 or less.

The invention relates to an optoelectronic emitter comprising a plurality of optical antennas, each comprising: a laterally emitting guiding structure formed from an injection waveguide and from a lateral diffraction grating configured to extract an optical mode in a horizontal plane; and a vertically emitting guiding structure formed from an emission waveguide configured to receive an optical mode extracted by the diffraction grating, and from a vertical diffraction grating configured to extract to free space an optical mode travelling through the emission waveguide.