116 results about "Refractive index profile" patented technology

The invention relates to the technical field of aerospace meteorology, and particularly discloses a domestic numerical weather forecast mode-based evaporation waveguide height determination method, which comprises the following steps of: obtaining meteorological coupling data output by a domestic numerical weather forecast mode CMA-MESO; determining parameters according to the meteorological coupling data and a turbulent flux algorithm COARE; constructing a temperature vertical profile and a specific humidity vertical profile according to the parameters, the Monin-Obchhoff similarity theory and an NPS model; constructing a modified refractive index profile according to the temperature vertical profile and the specific humidity vertical profile; and determining the height of the evaporation waveguide according to the height corresponding to the lowest point of the corrected refractive index profile. The method is suitable for determining the evaporation waveguide height in a domestic business meteorological mode.

The invention relates to the technical field of acoustic functional devices, and discloses an acoustic black hole lens based on a three-dimensional radial gradient refractive index phonon crystal structure and a design method, a three-dimensional radial gradient refractive index distribution function n (r) with a center convergence characteristic is constructed, and incident sound waves are continuously guided and efficiently focused to the center of the lens in the propagation process; combining the feasibility constraint of an additive manufacturing process, designing a few-negative micro-lattice structure unit for realizing the gradient refractive index distribution, and determining key geometric parameters of the few-negative micro-lattice structure unit; according to the refractive index distribution function n (r), radially arranging the micro-lattice units in a three-dimensional space, and constructing an initial lens model; the sound field distribution, focusing performance and energy convergence efficiency of the model are verified and iteratively optimized in a mode of combining analytical modeling and finite element method simulation, and a three-dimensional radial gradient refractive index photonic crystal acoustic black hole lens design model with wide-angle incidence compatibility and broadband response capability is obtained.

Disclosed are a method, a device, and an information processing program for determining, by using refractive index distribution data pertaining to an object to be observed, the region of a cell that has undergone programmed cell death in the object to be observed.

According to the deep ultraviolet laser epitaxial structure and the epitaxial growth method thereof provided by the invention, the Al component of the first waveguide layer is linearly and progressively increased from the side close to the electron injection layer to the side close to the quantum well active layer; or the Al component of the second waveguide layer is linearly and progressively decreased from the side close to the quantum well active layer to the side close to the hole injection layer to form refractive index distribution which takes the barrier layer of the quantum well active layer as the highest refractive index point and gradually decreases towards one side (the n-type side or the p-type side), so that the light field is firmly bound near the quantum well active layer, and the light limiting capability is remarkably enhanced; meanwhile, high-low Al components of the p-type side (the second waveguide layer) gradually change to generate a strong polarization electric field, ionization of a p-type doped acceptor (such as Mg) can be promoted, two-dimensional hole gas (2DHG) can be induced, and the hole concentration is improved; the low-high Al components of the n-type side (the first waveguide layer) are gradually changed, so that two-dimensional electron gas can be induced, and the electron concentration is improved.

Systems and methods are provided for improving overall vision in patients suffering from a loss of vision in a portion of the retina (e.g., loss of central vision) by providing symmetric or asymmetric optic with aspheric surface which redirects and / or focuses light incident on the eye at oblique angles onto a peripheral retinal location. The intraocular lens can include a redirection element (e.g., a prism, a diffractive element, or an optical component with a decentered GRIN profile) configured to direct incident light along a deflected optical axis and to focus an image at a location on the peripheral retina. Optical properties of the intraocular lens can be configured to improve or reduce peripheral errors at the location on the peripheral retina. One or more surfaces of the intraocular lens can be a toric surface, a higher order aspheric surface, an aspheric Zernike surface or a Biconic Zernike surface to reduce optical errors in an image produced at a peripheral retinal location by light incident at oblique angles.

The invention relates to a broadband bending-resistant multimode optical fiber and a preparation method thereof, the refractive index profile of a core layer is in a gradually-changed parabola shape, the distribution index alpha is 1.95-2.65, the radius R1 of the core layer is 12-35 microns, the delta 1max is 0.9%-1.4%, the relative refractive index difference delta 1min at the R1 position of the edge of the core layer is-0.16%--0.06%, cladding layers comprise an inner cladding layer, a first sunken cladding layer, a second sunken cladding layer and an outer cladding layer from inside to outside in sequence, the inner cladding layer is sequentially provided with a first inner cladding layer and a second inner cladding layer from inside to outside, the single-side width (R4-R3) of the first sunken cladding layer is 1.5-9.0 [mu] m, delta 4 is-1.1%--0.60%, the single-side width (R5-R4) of the second sunken cladding layer is 1.0-3.0 [mu] m, delta 5 is-1.0%--0.55%, the radius R6 of the outer cladding layer is 60-65 [mu] m, and delta 6 is-0.12-0.12%. The core cladding is reasonable in structural design, has the excellent characteristics of high bandwidth, strong bending resistance and low attenuation, and is high in transmission efficiency and excellent in long-term stability and reliability.

The application discloses a micro-nano grating and photocathode collaborative design method. The method breaks the traditional isolated design, and considers the micro-nano grating and the photocathode as an organic whole, and takes the spectral response or integral quantum efficiency of the system as a whole as a target function. Specifically, the method comprises the following steps: establishing a system structure model and clearly defining an optimization target and process constraints; establishing a complex refractive index-wavelength correlation model of the photocathode to accurately obtain a complex refractive index distribution; determining a set of parameters to be optimized and setting initial values; calculating the system electric field distribution under the current parameters based on an electromagnetic simulation model; combining the electric field distribution and the photoelectric emission mechanism to calculate the spectral response of the system in the target waveband; and using a parameter optimization algorithm to iteratively search the parameter space, and outputting an optimal parameter combination. The application fully considers the electromagnetic and photoelectric coupling between the two and the actual process constraints, has the advantages of high design accuracy, strong pertinence, good implementability and the like, and can significantly improve the detection sensitivity of a weak light detection device.

The application discloses a bending-insensitive high-bandwidth multi-mode optical fiber, which comprises a core layer, an extension layer, an inner cladding layer, a sunken cladding layer and an outer cladding layer arranged in sequence from inside to outside, the refractive index profile of the core layer is parabolic, the distribution index is 1.9-2.2, the maximum relative refractive index difference of the core layer center position is 0.9%-1.2%, the relative refractive index difference of the extension layer is -0.03% to -0.02%, the difference between the highest relative refractive index difference and the lowest relative refractive index difference of the inner cladding layer is 0.005%-0.03%, the single-side radial width of the inner cladding layer is 0.5-4 mu m, the single-side radial width of the sunken cladding layer is 3-9 mu m, and the relative refractive index difference of the sunken cladding layer is -0.7% to -0.4%. In the application, the optical fiber viscosity is optimized, the sensitivity of the optical fiber bandwidth to wavelength is reduced, the optical fiber has good bending resistance and super high bandwidth performance by reasonably designing the waveguide structure and the doping system.

Provided is an optical waveguide capable of suppressing optical loss in a groove portion into which a wavelength plate is inserted while eliminating polarization dependence. An optical waveguide according to the present disclosure is an embedded optical waveguide formed on a substrate, including a lower cladding; a core; an upper cladding; and a groove formed on one side of a side surface of the core with respect to a light propagation direction and extending in a direction parallel to the core, wherein a refractive index distribution in a plane perpendicular to the light propagation direction is a distribution in which a principal axis of a refractive index ellipse has a rotation amount with respect to a horizontal direction of the substrate.

In order to provide a display device with variable viewing modes and that can be manufactured inexpensively with less technical cost, it is proposed in a display device (100) that a control unit (16) is designed to cause dynamic changes in the radiation characteristics of the display device (100) by manipulating liquid crystal optical units (12, 12a, 12b). The display device includes a backlight unit (10), a liquid crystal display panel (11), at least one liquid crystal optical unit (12, 12a, 12b) and a control unit (16), wherein the liquid crystal optical unit (12, 12a, 12b) includes liquid crystal (13) that changes its refractive index profile according to an applied voltage (22).

The utility model relates to the field of optical fiber interference sensors, and discloses an M-Z interference sensor with a small excitation group velocity dispersion difference mode structure. Comprising a light injection single-mode optical fiber, a small-core-diameter step multimode optical fiber, a wide annular core optical fiber, an annular core optical fiber, a gradient refractive index multimode optical fiber, a large-core-diameter step multimode optical fiber and a light receiving single-mode optical fiber which are connected in sequence. The wide annular core optical fiber comprises a third quartz cladding and a third quartz fiber core, and the third quartz fiber core annularly wraps a third quartz layer; the annular core optical fiber comprises a fourth quartz inner wrapping layer, a fourth quartz fiber core and a fourth quartz outer wrapping layer, the fourth quartz inner wrapping layer is annularly wrapped by the fourth quartz fiber core, the fourth quartz fiber core is annularly wrapped by the fourth quartz outer wrapping layer, and the optical fiber radial refractive index distribution index of the gradient refractive index multimode optical fiber is 1.95-2. According to the scheme, the annular core optical fiber is used for injecting light to the gradient refractive index multimode optical fiber, two modes with smaller group velocity dispersion difference can be excited to interfere, and the sensitivity of the sensor is improved.

An image display device according to one embodiment of the present disclosure comprises: a plurality of display pixels which are arranged in a two-dimensional array form; active layers which are respectively provided to the plurality of display pixels or which are provided straddling the plurality of display pixels; and a photonic crystal layer which is provided to at least some of the plurality of display pixels, which includes a defect in a periodic refractive index distribution that disrupts said periodic refractive index distribution, and in which neither the outer shape of the region having the periodic refractive index distribution nor the structure in the vicinity of the defect has rotational symmetry with respect to rotations of less than 180°.

The application discloses a seawall protection structure design method and system based on a winding space metasurface technology, relates to the technical field of seawall protection engineering, and comprises the following steps: selecting a suitable winding space metasurface unit model according to frequency parameters and wave height parameters of sea waves; designing and optimizing the winding space metasurface unit model based on a preset refractive index distribution; arranging and installing the designed winding space metasurface unit model array outside a seawall and debugging; and adjusting the arrangement and refractive index of the winding space metasurface unit model to cope with different sea wave conditions by monitoring sea conditions in real time. The application modulates the energy distribution of water surface waves, realizes focusing, scattering or absorption of the waves, effectively reduces the direct impact of the sea waves on the seawall, enhances the protection effect, and reduces the long-term maintenance cost.

The application discloses a preparation method, product and device of a square core optical fiber preform. The preparation method comprises the following steps: (1) making the rotating central axis of a Leilo triangular drill bit coaxial with the geometric central axis of a circular cavity cladding sleeve, and drilling a rounded square with the width d as the side length by using the Leilo triangular drill bit to obtain a square cavity cladding sleeve; (2) sleeving a square core rod with the width d' into the square cavity cladding sleeve, and stretching or fusing the square core rod into a circular solid rod; and (3) manufacturing the square core optical fiber preform according to the designed shape size and refractive index profile. The Leilo triangular drill bit is designed according to the width fixing principle of the Leilo triangular structure, and can be used for square hole processing of brittle materials such as quartz glass. The optical fiber prepared by using the square core rod and the square hole sleeve combination drawing reduces the probability of uncontrollable core-cladding interface air line occurrence caused by the original square core rod and circular sleeve combination drawing, and guarantees the reliability of the optical fiber.

A multicore optical fiber is provided including a first core region having a first refractive index profile, a second core region having a second refractive index profile, wherein the first core region is separated from the second core region by a separation distance in a range of 20-50 μm, and an outer cladding surrounding the first and second core regions, wherein the first core region exhibits a first effective index and a first group index and the second core region exhibits a second effective index and a second group index, and the first and second effective indices are substantially different to suppress crosstalk and the first and second group indices are substantially the same to achieve a substantially similar group velocity.

The application discloses a high-power single-mode linear polarization Raman fiber laser based on a multimode optical fiber, and is characterized in that: a Raman gain medium of the laser is a single-clad circularly symmetric step-index distribution large-core multimode optical fiber; a base mode diameter of the step-index large-core multimode optical fiber is more than 65% of a core diameter; a Bragg fiber grating is inscribed in the core of the multimode optical fiber by using a femtosecond laser direct writing technology; a long axis of the grating region is coincided with a base mode field supported by the multimode optical fiber in a radial direction in space and length; the grating forms selective optical feedback only to the base mode in the cavity; a grating region with a difference between the long axis and the short axis forms selective feedback to one polarization state of the base mode; thus, the multimode optical fiber Raman laser effectively suppresses generation of mode instability at a high power level through active mode cleaning, and finally realizes near-diffraction-limited single-mode, high linear polarization and high-power Raman fiber laser output.

An optical connection component includes a glass member and an optical waveguide. In a refractive index distribution of the optical waveguide along a first direction, when the distance from the center to the outer edge of the optical waveguide along the first direction is denoted by r, the refractive index at the position of the outer edge is denoted by nr1.0, the refractive index at a position away from the center by 20% of the distance r is denoted by nr0.2, and the refractive index at a position away from the center by 80% of the distance r is denoted by nr0.8, the ratio (nr0.2 / n1) of the refractive index nr0.2 to the refractive index n1 is 85% or more and 100% or less, and the ratio (nr0.8 / n1) of the refractive index nr0.8 to the refractive index n1 is 8% or more and 75% or less.

This optical communication system comprises: an optical transmission unit that includes a light source for outputting laser light having a spectral width of 0.1 nm or greater in an oscillation spectrum and a signal generator for applying a modulation signal of 25 GBaud or greater to the light source, the optical transmission unit outputting a modulated optical signal in which the laser light is modulated by the modulation signal; and an optical fiber that is composed of a plastic which contains fluorine atoms in at least the core thereof, the optical fiber being such that the absolute value of material dispersion at a wavelength within the spectral width of the modulated optical signal is less than the absolute value of material dispersion in quartz glass, having a length of 100 m or less, having a GI-type refractive index distribution, and propagating the modulated optical signal.

The invention discloses a shipborne marine atmospheric boundary layer refractive index profile detection system and method, and relates to the technical field of marine atmospheric environment monitoring and electromagnetic wave propagation safeguard.The method comprises the steps that sea-air downlink infrared radiation spectrum data and sea surface air temperature, relative humidity and air pressure data are obtained; constructing a background atmosphere profile by using the reanalysis data, and correcting an initial profile bottom layer by using sea surface observation air temperature, relative humidity and air pressure data to form a prior state vector; constructing an inversion cost function including an observation residual term, a background prior term and a sea surface boundary constraint term, and performing inversion to obtain an atmospheric temperature profile and a relative humidity profile; and calculating an atmospheric refractive index profile according to the temperature profile, the relative humidity profile and the air pressure profile. According to the method, the marine atmospheric refractive index profile can be continuously obtained under the shipborne dynamic observation condition, and reliable data support is provided for marine electromagnetic propagation environment analysis and waveguide diagnosis.

The invention discloses a wide-spectrum optical anti-reflection structure with continuous gradient refractive index distribution and preparation and application of the wide-spectrum optical anti-reflection structure. Comprising a substrate made of a first optical material; the microsphere array is arranged on the surface of the substrate and is made of a second optical material, and the refractive index of the second optical material is between the refractive index of the incident medium and the refractive index of the first optical material; wherein the microsphere array is a single-layer array, and the microsphere array is in contact with or embedded into the surface of the substrate to form a composite interface structure; in the depth direction, the composite interface structure presents the refractive index distribution of continuous gradual change from the incident medium to the refractive index of the second optical material. By adjusting the size and the embedding depth of the microspheres, the effective refractive index distribution can be flexibly regulated and controlled, reflection inhibition or absorption enhancement in a wide-angle and wide-spectrum range is realized, and the bionic characteristic and the adjustable optical performance are realized.

The application belongs to the technical field of optical precision measurement, automation control and artificial intelligence, and particularly relates to an interference optical path for obtaining multiple information in single exposure and application thereof, the interference optical path comprising: rotating a polarization direction of a light source through a half-wave plate to obtain first linearly polarized light; the first linearly polarized light is evenly divided into reference light and test light by a common beam splitter; the reference light passes through a quarter-wave plate back and forth to obtain second linearly polarized light orthogonal to the first linearly polarized light; the test light is decomposed into third linearly polarized light and fourth linearly polarized light by a Wollaston prism; the third linearly polarized light and the fourth linearly polarized light irradiate on a measured object, pass through the Wollaston prism again after reflection, and are combined with the second linearly polarized light at the common beam splitter; the combined light beam is received by a polarization resolution camera and records interference signals.The application can realize absolute phase reconstruction in single exposure, and is suitable for measuring refractive index distribution of dynamic or environment-sensitive samples.

The invention discloses a method for adaptively adjusting the coiling diameter of a gain optical fiber and a laser system, and relates to the field of optical fiber lasers, and the method comprises the steps: obtaining the temperature of the gain optical fiber under the current coiling diameter and the current LD current; determining the current transverse refractive index distribution of the gain fiber according to the temperature of the gain fiber based on a thermo-optic effect and a numerical modeling mode; according to the current transverse refractive index distribution, bending loss curves of conduction modes LP01 and LP11 in the gain fiber are calculated; according to a preset optimization principle, the optimal coiling diameter of the gain fiber is determined according to the bending loss curves of the conduction modes LP01 and LP11; the optimal coiling diameter is used as an adjustment basis of the coiling diameter of the gain fiber. The coiling diameter of the gain optical fiber is automatically adjusted according to self-adaptive feedback according to the temperature of the optical fiber, so that the TMI threshold value is increased.

A system including a mode coupler has at least one waveguide section connected between a mode coupler input and a mode coupler output. The waveguide section supports a set of guided coupler modes and a set of cutoff coupler modes, and has a transverse refractive index profile and a longitudinal refractive index profile. The transverse refractive index profile is adjusted by free-form optimization to yield a set of desired spacings between a set of propagation constants of the sets of coupler modes such that the longitudinal refractive index profile induces desired couplings between the guided coupler modes, while inhibiting undesired couplings between the guided coupler modes and the cutoff coupler modes, and undesired couplings between the guided coupler modes.

The invention belongs to the field of optical fiber lasers, discloses a simulation-based mode field adapter for an optical fiber laser and a preparation method thereof, and is particularly suitable for low-loss coupling from a large-mode-field optical fiber to a single-mode optical fiber of 980nm-band pumping laser. The method comprises the following steps: firstly, optimizing refractive index distribution of a self-focusing optical fiber through optical simulation, determining a period parameter P and verifying that theoretical fundamental mode loss is less than or equal to 0.18 dB; based on this, the length of the self-focusing optical fiber is set to be a half-cycle integral multiple structure (L = n.P + 0.5 P, n > = 1). In an experiment, a thermal core expanding process is combined, and efficient coupling from a large-mode-field optical fiber to a single-mode optical fiber is achieved. According to the scheme, the industrial problem that a traditional adapter is high in loss in the large-to-small mode field direction is solved, and low loss of 0.45 dB is achieved in the 980 nm wave band. And meanwhile, the complex mode field measurement requirement is avoided, and the transmission efficiency of the pumping laser is remarkably improved. The adapter is especially suitable for an optical fiber laser output end coupling scene, and breaks through the limitation that an existing adapter is only suitable for a small-to-large mode field direction.

The present disclosure provides an active large mode field area (LMA) optical fiber for mitigating transverse mode instability (TMI) effects. The active LMA fiber includes an inner core and one or more claddings surrounding the inner core. The inner core has an inner core diameter and an annular refractive index reduction zone located in a lateral plane of the LMA fiber. The outer diameter of the annular refractive index reduction region is smaller than the diameter of the inner core, and the local refractive index thereof is lower than the refractive index in the rest of the cross section of the inner core. The inner core has an inner core glass composition comprising one or more rare earth dopants and at least one co-dopant. The inner core glass composition defines a radial refractive index profile in the inner core of the active LMA optical fiber, the radial refractive index profile including a recess along the annular refractive index reduction region.

A rod lens array (10a) has a plurality of refractive index distribution type rod lenses (1b) arranged in parallel with their optical axes, forming a positive erect equal magnification image. The refractive index distribution type rod lens (1b) has a refractive index distribution in the radial direction. The radius of the refractive index distribution type rod lens (1b) is denoted as r0. The refractive index at the center of the refractive index distribution type rod lens (1b), that is, the central refractive index, is denoted as n0. The refractive index distribution constant of the refractive index distribution type rod lens (1b) is denoted as A such that the refractive index at a distance r from the center of the refractive index distribution type rod lens (1b) is approximated as n(r) = n0·{1-(A / 2)·r 2}. The opening angle θ represented by the formula is 3-6°. The imaging distance of the rod lens array (10a) is 45-75 mm. The depth of field in which the value of the modulation transfer function (MTF) at a spatial frequency of 6 lp / mm is 30% or more is 1.5-3.0 mm.

The invention discloses a thick curved surface sample rapid three-dimensional imaging system and method based on multi-angle illumination, and relates to the technical field of optical imaging. The method comprises the following steps: providing multi-angle illumination through an illumination array, and collecting an intensity image sequence of a thick curved surface transparent sample at different illumination angles and rotation orientations; based on a frequency domain laminated imaging principle, recovering high-resolution complex amplitude projection through frequency domain sub-aperture synthesis and joint constraint iteration; and reconstructing the three-dimensional refractive index distribution in the sample through a tomographic inversion algorithm. The corresponding system comprises an illumination module, a sample bearing module, an image acquisition module and a control processing module. According to the method, the problem of information loss caused by the refraction effect of the thick curved surface transparent sample is effectively solved, rapid, lossless and high-precision three-dimensional refractive index imaging is realized, and an effective detection means is provided for precision manufacturing and scientific research.

This invention provides a broadband high-power superluminescent diode based on tunnel junction cascade, comprising an epitaxial structure and matched n-electrodes and p-electrodes. The epitaxial structure includes an n-type confinement layer, a p-type confinement layer, x light-emitting structures, and (x-1) tunnel junctions. The x light-emitting structures and (x-1) tunnel junctions are disposed between the n-type and p-type confinement layers along the epitaxial growth direction. Each tunnel junction is disposed between two adjacent light-emitting structures, and the two adjacent light-emitting structures are electrically cascaded via the tunnel junctions. The n-type and p-type confinement layers form a unique pair of confinement layer structures, and the x light-emitting structures operate together within the same pair of confinement layer structures. By setting a unique pair of confinement layer structures, this invention eliminates the multi-waveguide characteristics of the longitudinal refractive index distribution, thereby suppressing longitudinal multimode and near-field multi-peak phenomena, significantly improving the coupling efficiency and beam quality of the device, and simultaneously achieving high power and broadband output.

The present application relates to an optical encryption device, an optical decryption device and an optical encryption communication system, the encryption device comprising: a control unit for generating a control signal based on a pre-encryption protocol; an optical control unit for encoding the plaintext optical signal based on the control signal to obtain the ciphertext optical signal; wherein the encryption protocol is based on the correspondence between the refractive index distribution of the optical control element and the control signal; the optical control element comprises an electrically controllable adjustable scattering medium, the electrically controllable adjustable scattering medium comprises a plurality of tunable anisotropic micro elements, and the refractive index distribution of the electrically controllable adjustable scattering medium can be changed based on the control signal loaded thereon. The system of the present application has good response speed and response accuracy, so as to improve the communication efficiency and communication quality of the communication system under the premise of ensuring the communication security.

The application provides a method, device and equipment for calculating the refractive index distribution of a corona discharge channel and a storage medium, and the method comprises the following steps: obtaining a schlieren image of corona discharge, determining a light deflection angle correction curve corresponding to a target discharge channel; determining an original deflection angle corresponding to each pixel point in the schlieren image of corona discharge; performing interpolation processing on the original deflection angle corresponding to each pixel point, determining the axis of the target discharge channel according to the deflection angle data points, and determining an axial symmetry coordinate system of the schlieren image of corona discharge; determining the corresponding relationship between the deflection angle data points and the refractive index based on a preset Abel integral formula and the axial symmetry coordinate system, and solving the singular points of the Abel integral formula by approximation; and calculating the radial distribution data of the refractive index of the target discharge channel according to the singular points obtained by approximation and the corresponding relationship between the deflection angle data points and the refractive index. The application can increase the amount of reference information provided by the corona discharge detection technology to meet the quantitative analysis requirements of corona discharge.