6260 results about "Wavelength" patented technology

The invention discloses an on-line detection method for gas in transformer oil based on photoacoustic spectrum self-correction, and relates to the technical field of spectrum detection and power equipment state monitoring, and the method comprises the following steps: S1, emitting modulation laser with a specific wavelength to a gas sample released by the transformer oil through a laser, and exciting gas molecules to generate photoacoustic signals; and S2, detecting the photoacoustic signal by using a photoacoustic sensor, converting the signal into an electric signal, and outputting the electric signal. According to the online detection method for the gas in the transformer oil, the correction coefficient is adjusted in real time through a self-correction algorithm, errors caused by light path changes and sensor aging are effectively compensated, the precision and stability of long-term detection are remarkably improved, and the detection accuracy is improved by combining a gas spectrum database and a mode recognition algorithm. According to the method, accurate qualitative and quantitative analysis of various gases is realized, the problem of cross sensitivity of multiple components is solved, and the method also has temperature and pressure compensation functions and can automatically adapt to environmental changes.

The invention discloses a shield tunnel active and passive source combined geological detection method and system. The method comprises the following steps: acquiring an active source seismic wave reflection signal and a passive source acoustic wave reflection signal; according to the active source seismic wave reflection signal, obtaining an active source geological detection imaging result by adopting a longitudinal and transverse wave combined imaging principle; according to the passive source sound wave reflection signal, a frequency dispersion extraction-shear wave velocity inversion method fusing spatial autocorrelation and a half-wavelength model is adopted to obtain a passive source geological exploration imaging result; and taking an active source geological detection imaging result as a main result, taking a passive source geological detection imaging result as an auxiliary result, and combining adaptive adjustment coefficients between the two results to obtain an unfavorable geological risk level of the to-be-detected area. Shield tunneling vibration noise with high energy and wide frequency band is introduced as a passive detection source, the detection depth and resolution are improved, and support is provided for accurate geological imaging.

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

The invention relates to the technical field of three-dimensional imaging, and discloses a high-precision underwater structured light three-dimensional point cloud imaging method and system, and the method comprises the following steps: deploying a plurality of sensor nodes, monitoring the temperature, salinity and turbidity key parameters of a water body in real time, selecting proper light source wavelength and power according to the collected data, and carrying out the three-dimensional point cloud imaging of the underwater structured light. It is ensured that the optimal signal-to-noise ratio is obtained under the current condition, and meanwhile the exposure time and gain setting of the camera are initialized. According to the method, the optimal signal-to-noise ratio is obtained by monitoring water body conditions in real time and dynamically adjusting light source characteristics, the optimal structured light pattern is predicted by using a machine learning model, scattering noise is removed, advanced registration and fusion algorithms and an accurate phase unwrapping method are applied, and a high-quality comprehensive structured light pattern is generated. Point cloud gaps are filled through a geometric correction algorithm and an interpolation / filtering algorithm, so that a reconstruction model is closer to the surface of a real object.

Meta-optic systems are described that include multi-function metasurfaces formed from a plurality of meta-atoms. A multi-function metasurface can exhibit two or more different optical functions for two or more different states of light incident on the metasurface. Different states of light include different polarizations, different wavelengths, and different angles of incidence. Different optical functions include distance sensing, converging, diverging, image formation, and patterned light formation. The multi-function metasurface can selectively impart different phase profiles to an incident beam depending on the incident beam's state of light.

A processing method of a workpiece with a circular disc shape includes sticking a tape to one surface of the workpiece and integrating the workpiece and a frame through the tape, holding the workpiece by a holding unit with the interposition of the tape, and irradiating the other surface of the workpiece located on the opposite side to the one surface with a pulsed laser beam having such a wavelength as to be absorbed by the workpiece from the side of the other surface. In irradiating the laser beam, the other surface is annularly irradiated with the laser beam in the state in which the orientation of the laser beam is adjusted in such a manner that the laser beam has an angle of incidence formed due to inclination with respect to a normal to the other surface of the workpiece by a predetermined angle.

A method for overlay metrology may include generating broadband illumination beams and directing the broadband illumination beams to an overlay target on a sample, where the overlay target may include cells having periodic features formed as overlapping grating structures. The method may include generating diffracted light using the periodic features of the overlay target, where the periodic features may act as a diffraction grating to generate diffracted light by separating the broadband illumination beam into a plurality of wavelengths. The method may include generating pupil images of cells of the overlay target, where a distribution of light in the pupil plane may include first-order diffraction lobes, where spectra of the first-order diffraction lobes may be spatially dispersed in the pupil plane. The method may include generating an overlay measurement based on portions of the pupil images corresponding to selected wavelengths of the spectra of the first-order diffraction lobes.

The invention relates to the technical field of spectral data processing, and provides a soil heavy metal content detection and correction method based on an X-ray fluorescence spectrum, which comprises the following steps: acquiring a plurality of XRF spectral signals of a to-be-detected soil sample as an original spectral curve; obtaining the overall similarity of each original spectrum curve and the initial interference weight of each peak point in the original spectrum curves; decomposing to obtain a plurality of component signals; constructing a plurality of local windows of each component signal; obtaining a noise interference factor of each local window in each original spectrum curve; obtaining an adjustment reference coefficient of each local window in each original spectrum curve; obtaining a filtering adjustment coefficient of each wavelength in each original spectrum curve; dynamically filtering and smoothing the original spectrum curve to obtain a to-be-measured spectrum signal; and detecting the soil heavy metal content based on the to-be-detected spectral signal. The invention aims to solve the problem of heavy metal content detection deviation caused by noise in an X-ray fluorescence spectrum.

A device implementing a nonlinear activation function including a material having nonlinear susceptibility phase-matching a coherent nonlinear interaction involving a signal comprising a signal wavelength and a bias comprising a bias wavelength, so that (1) a first phase difference between the signal and the bias induces the interaction comprising second harmonic generation (generating a second harmonic of the bias wavelength) or sum frequency generation (generating a sum frequency of the bias and the signal, and (2) a second phase difference between the signal and the bias induces the interaction comprising parametric amplification amplifying the bias and attenuating the signal. A positive input to the nonlinear activation function is represented by the signal having an input energy and the first phase difference. A negative input is represented by second phase difference. The output is an output energy of the signal as function of the input energy.

The present invention belongs to the technical field of LiDARs, and particularly relates to a system and method for synchronous detection of atmospheric data in the same path. The detection system comprises a transmitting unit, a receiving unit and a data processing unit, wherein the transmitting unit comprises a plurality of laser devices, and is used for synchronously transmitting laser having different wavelengths in a common path; the receiving unit comprises a receiving telescope, which is symmetrically provided with a plurality of sub-apertures used for receiving echo signals that are generated after the laser having different wavelengths interacts with the atmosphere; and the data processing unit is used for calculating atmospheric data parameters by means of the echo signals. By means of the present invention, synchronous detection of a plurality of atmospheric data parameters in the same path can be implemented.

The invention relates to the technical field of optical detection, in particular to a glass bottle surface spraying quality detection method which comprises the following steps: under a specified wavelength, acquiring target incident light by adjusting a polarization angle, irradiating a glass bottle spraying layer, collecting a transmission spectrum signal to calculate parallel and vertical polarization transmissivity and ratio of the spraying layer, and generating polarization transmissivity. According to the method, the light with the polarization angle irradiates the spraying layer, the polarization component of the transmission light is obtained, the thickness uniformity and the internal structure are analyzed, weak areas, particle flaws and excessive spraying of the spraying layer are recognized, the defect detection precision is improved, multi-angle transmissivity data are collected, the change rate is calculated, and color deviation and thickness abnormity are accurately positioned; through cross analysis of multiple optical parameters, evaluation of adhesive force, curing quality and color consistency is more detailed, spraying abnormity is classified, multiple detection means act synergistically, interference such as environment illumination and material reflectivity is reduced, and the detection accuracy of spraying quality is improved.

The invention relates to the related technical field of semiconductor wafers, in particular to a full-automatic wafer film thickness detection method and system based on spectral reflection, and the method comprises the steps: obtaining a wafer surface reflection spectral signal, and extracting spectral feature information and wavelength parameters; identifying a polarization characteristic parameter and an interface interference characteristic parameter, introducing the wavelength parameter as an adjusting variable, determining a wavelength dependence term, and generating a global film thickness distribution map, thereby solving the problems that in a detection scene with a multi-layer film or a rough interface, the influence of an incident light polarization state on a reflection signal is not fully considered, the reflection signal characteristic extraction is distorted, and the detection accuracy is poor. According to the method, the technical problem that the film thickness obtained through reflection characteristic backstepping deviates from the actual film thickness is solved, polarization characteristic parameters and interface interference characteristic parameters are recognized, the thickness of each detection point is determined after the film refractive index is corrected, the thickness detection precision is effectively improved, and the influence of spectral signal noise and interface interference is reduced; the technical effect of accurately presenting the global film thickness distribution of the wafer film is achieved.

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.

An example apparatus, method, and system for determining a characteristic of a target gas in a fluid sample is provided. In some embodiments, the example apparatus includes a frequency comb illumination source configured to emit pulsed light having a plurality of frequency comb wavelengths. The apparatus also includes an optical cavity containing a fluid sample and exhibiting a plurality of cavity resonance modes. A frequency comb wavelength of the plurality of frequency comb wavelengths associated with the frequency comb illumination source is configured to align with a cavity resonance mode of the plurality of cavity resonance modes. A characteristic of the fluid sample is determined based on one or more optical characteristics of a transmitted light passing through the fluid sample within the optical cavity.

The present disclosure provides an optical component, which may be a metasurface grating, including (a) a substrate; and (b) an array of subwavelength-spaced phase-shifting elements, which are tessellated on the substrate to produce, when illuminated with a polarized incident light, a diffracted light beam with a distinct polarization state for each of a finite number of diffraction orders, wherein the finite number is 2 or more.

The invention relates to a method and a system for detecting the concentration of trace methane by locking the position of an absorption peak, and belongs to the technical field of laser gas detection. Modulated laser output by a laser is divided into two paths, one path enters a reference light path, the other path firstly passes through a gas absorption cell and then enters an actual detection light path, and methane gas with known concentration is sealed in the reference light path; demodulating a modulation signal output by the actual detection light path, and calculating to obtain a trace methane gas concentration value; and demodulating the modulation signal output by the reference light path to obtain a second harmonic signal, comparing the amplitude of the second harmonic signal with the amplitude of a harmonic signal corresponding to a preset methane absorption peak to generate a wavelength shift error signal, and adjusting the driving parameter of the laser through a feedback mechanism to generate a wavelength shift error signal. The output power and wavelength drift of the laser are monitored in real time, and it is ensured that the laser wavelength is always locked within the methane absorption peak range. According to the invention, high-precision and high-stability trace methane concentration detection can be realized.

The invention discloses a method and a system for measuring an error caused by wavelength drift of an optical fiber current transformer. The method comprises the following steps: constructing a first mathematical model of a half-wave voltage size and a wavelength size, and a second mathematical model of a Verdet constant and the wavelength size; according to the first mathematical model and the second mathematical model, constructing a third mathematical model of the Verdet constant and the half-wave voltage; and constructing a fourth mathematical model of the output optical signal and the half-wave voltage, and determining the total influence of the wavelength drift on the output optical signal according to the fourth mathematical model. The error of wavelength drift can be effectively compensated, and the measurement performance of the optical fiber current transformer is improved.

The invention provides a wavelength deviation compensation method and system for rapid wavelength analysis of a far-end fiber bragg grating, and relates to the technical field of fiber bragg grating sensing, and the method comprises the steps: collecting grating reflection spectrum signals of different transmission distances, carrying out frequency domain transformation to separate phase components, and building a mapping relation between the transmission distance and dispersion cumulant; calculating an initial wavelength offset estimation value; identifying a refractive index section, and establishing a segmentation compensation coefficient; constructing a wavelength-strain-temperature three-dimensional space, and optimizing a compensation coefficient according to the trajectory curvature; and updating the compensation coefficient according to the residual gradient. The wavelength analysis precision of the far-end fiber bragg grating can be improved, and the influence of dispersion on measurement is reduced.

An apparatus may include a platen, a light source system, an ultrasonic receiver system and a control system, the light source system configured for providing first light of a first wavelength and second light of a second wavelength to a target object on an outer surface of the platen. The control system may be configured to: cause the light source system to provide the first light to the target object at a first time and to provide the second light to the target object at a second time; receive first ultrasonic receiver signals and second ultrasonic receiver signals from the ultrasonic receiver system corresponding to photoacoustic responses of the target object to the first light and the second light, respectively; and estimate one or more blood vessel features based on at least one of the first ultrasonic receiver signals or the second ultrasonic receiver signals.

The invention discloses a method and a device for inhibiting laser wavelength temperature drift, relates to laser wavelength measurement and laser frequency stabilization, and belongs to the field of atomic physics and quantum optics. The device comprises a laser output light unit, a high-precision wavemeter monitoring unit and a temperature drift feedback control unit. And measuring a wavelength drift coefficient a of environment temperature T environment-laser wavelength lambda. Measuring a set temperature Tset-laser wavelength lambda and a wavelength control coefficient b; and according to the measured coefficients a and b, calculating to obtain a temperature gradient compensation coefficient c (c = a / b). When the laser works normally, the T environment is collected in real time, and the set temperature Tset of the laser is changed according to the temperature gradient compensation coefficient c and the T environment, so that the laser wavelength temperature drift is inhibited. According to the invention, active suppression of laser wavelength temperature drift is realized by regulating and controlling a temperature gradient compensation coefficient. The device has the advantages of being simple in structure, high in wavelength drift suppression capability, low in energy loss and the like.

An electronic interface device is configured for use with associated optics for employing coded light for illuminating a liquid, gaseous, or other analyte or target, such as for measuring or determining a composition or other property of the analyte or target. The arrangement can help enable a far higher level of performance, such as for spectral analysis, imaging, or both. A shared common clock on both the illumination and receive sides of the system can be included, such as together with one or more of reference detection, per-channel wavelength-dependent modulation, multiple concurrent feedback loops at different levels, orthogonal and circulant codes, phase-scrambling to better utilize ADC dynamic range, oversampling, and other signal processing can be provided.

Methods and systems are provided to generate and use pairs of highly nondegenerate frequency-entangled photons for Hong-Ou-Mandel interferometric measurement of local or remote samples. The use of highly nondegenerate frequency-entangled photon pairs enables ultra-high spatial resolutions even in the presence of background noise, dispersive intermediate media and / or dispersive or multi-interface targets, and high probe photon losses. The use of highly nondegenerate, narrow-band, frequency-entangled photon pairs for interferometric measurement of distance also allows the interferometer to be calibrated more easily for the two (or more) discrete narrow bands of wavelengths represented by the photon pairs. The use of narrow-band nondegenerate frequency-entangled photon pairs also permits improved noise rejection and increased fidelity in coincidence detection.

The invention discloses a vertex measurement device and method based on a spectral confocal technology, and the method comprises the steps: transmitting a plurality of light beams through a plurality of light-emitting apertures which are arranged in a preset geometrical shape, carrying out the dispersion of the plurality of light beams into dispersion light beams with different wavelengths through a dispersion lens, irradiating the dispersion light beams to the surface of a measured workpiece, receiving reflected light, and carrying out the measurement of the measured workpiece. The reflected light is transmitted to the spectrum analysis device through a corresponding optical fiber channel; the spectrum analysis device analyzes the light intensity and wavelength of each group of reflected light and extracts spectrum data; calculating the height or space coordinate of the vertex of the surface of the workpiece according to the change condition of the spectral data of each group of reflected light rays; the processing circuit outputs the calculated vertex height or space coordinate information; according to the method, the vertex information of the workpiece can be effectively derived through ingenious spectral analysis and geometric fitting technologies, and the method has wide applicability and is particularly suitable for vertex measurement scenes of high-precision spherical surfaces, aspheric surfaces and conical surfaces.

There is provided a chromatic dispersion measurement method and system for characterizing an optical fiber link under test. From a proximal end of the optical fiber link, at least one OTDR acquisition is performed, wherein each OTDR acquisition is performed by propagating in the optical fiber link under test, at least one test signal comprising a plurality of light pulses in accordance with a known sequence of pulses and detecting corresponding return light signal from the optical fiber link so as to obtain a trace representing backscattered and reflected light as a function of distance in the optical fiber link under test, and wherein said test signals have mutually different wavelengths. For each test signal and corresponding wavelength, a position of the reflective peak associated with a remote end of the optical fiber link is extracted from the return light signal by calculating a cross-correlation between the known sequence of pulses and the acquired trace. A value of a chromatic dispersion coefficient associated with said optical fiber link is then calculated from values of the extracted positions and corresponding wavelengths.

The invention provides a super lens and a femtosecond laser manufacturing real-time monitoring system applying the super lens, the super lens comprises a substrate and a nano column array on the substrate, nano columns at different positions in the nano column array independently regulate and control a first wavelength light wave and a second wavelength light wave, so that the first wavelength light wave satisfies first phase distribution, and the second wavelength light wave satisfies second phase distribution. The second wavelength light wave meets the second phase distribution, so that the super lens not only can focus the first wavelength light wave and the second wavelength light wave on the same plane, but also can control the focal depth of the first wavelength light wave to be greater than the focal depth of the second wavelength light wave, so that the requirement of a femtosecond laser manufacturing real-time monitoring system is met; not only can the anti-interference capability in the machining process be improved, but also the axial position monitoring precision can be improved.

The invention discloses an egg quality detection system and method based on multi-sensor fusion, and relates to the technical field of multi-dimensional data process.The method comprises the steps that texture features are extracted from visible light images, and feature wavelengths are extracted from spectrums; pressure distribution and shell deformation in the pressing process are synchronously collected; recording a pressure-time curve and a deformation-time curve, extracting characteristic parameters, and constructing a three-dimensional dynamic model; performing wavelet transformation on the response curve of each sensor, extracting time-frequency domain characteristics, and generating a smell fingerprint spectrum; scanning the surface of the egg to excite resonance response, recording a sound pressure signal, and converting the sound pressure signal into frequency domain data through fast Fourier transform; and presetting a business rule, and generating a final decision by combining the model output with a rule matching result. The pressure feature extraction module, the smell feature extraction module and the crack degree quantification module are arranged to realize data depth association, and the quality inspection credibility is improved through an interpretable decision model.

A light absorber 10 has a transmission spectrum satisfying the following requirements (I), (II), (III), (IV), and (V) at an incident angle of 0°. The light absorber 10 has a haze less than 0.20%. (I) An average transmittance TA0deg(460-600) is 75% or more. (II) A shorter cut-off wavelength λH0deg(s) is in a range of 390 nm to 450 nm. (III) A longer cut-off wavelength λH0deg(L) is in a range of 600 nm to 680 nm. (IV) An average TA0deg(300-380) is 1.2% or less. (V) An average TA0deg(750-1000) is 1.2% or less.

The invention relates to the technical field of semiconductor lasers, in particular to a laser based on a bimetallic Bragg grating and a top SiO2 waveguide layer, which comprises a gain chip, the left end face of the gain chip is plated with a first high-reflection HR film, and the right end face of the gain chip is plated with a first anti-reflection AR film; a metal Bragg grating waveguide is arranged on the right side of the gain chip, the right end face of the gain chip and the left end face of the metal Bragg grating waveguide are aligned and attached to form an outer cavity structure, and the left end face of the metal Bragg grating waveguide is plated with a second anti-reflection AR film. The right end face of the metal Bragg grating waveguide is plated with a third anti-reflection AR film. According to the invention, a temperature change test is carried out, and the wavelength drift is controlled to be + / -0.002 nm in a range of-40 DEG C to 85 DEG C; performance test results show that the line width is 0.6 kHz, the SMSR is 65 dB, and the threshold current is 22 mA.

An apparatus may include a platen, a light source system, an ultrasonic receiver system and a control system, the light source system configured for providing first light of a first wavelength and second light of a second wavelength to a target object along a first axis. The control system may be configured to: cause the light source system to provide the first light to the target object at a first time and to provide the second light to the target object at a second time; receive first ultrasonic receiver signals and second ultrasonic receiver signals from the ultrasonic receiver system corresponding to photoacoustic responses of the target object to the first light and the second light, respectively; and estimate one or more blood vessel features based on at least one of the first ultrasonic receiver signals or the second ultrasonic receiver signals.

The invention relates to the technical field of optical elements, in particular to a method for predicting damage evolution of an optical element based on laser irradiation, which comprises the following steps: firstly, acquiring physical parameters (oxygen-silica ratio, transmissivity and absorption coefficient) and laser irradiation parameters (wavelength, energy density and repetition frequency) of the optical element; mapping the relationship between the environmental parameters and the damage threshold; constructing an oxygen-silica ratio-transmissivity-damage threshold correlation model, and analyzing evolution of physical parameters along with laser emission; the method comprises the following steps: establishing a heat-light-force multi-physics field coupling model, exploring a damage mechanism, finally predicting damage threshold evolution of the optical element after irradiation of different lasers through the models, obtaining a damage threshold change trend curve and a critical damage point, and establishing a damage prediction model based on physical parameters. Therefore, the damage evolution of the optical element is predicted in advance, the experimental period is shortened, and the evaluation efficiency is improved.