12 results about "Nonlinear spectroscopy" patented technology

The invention relates to the technical field of ground feature component analysis, and discloses a hyperspectrum-based mineral alteration feature extraction method, which comprises the following steps: acquiring hyperspectral remote sensing image data of a to-be-processed region, and carrying out atmospheric correction and noise reduction preprocessing; extracting an initial end member spectrum after preprocessing; constructing an objective function of nonlinear spectral unmixing, wherein the objective function comprises a data fidelity term; an abundance constraint term; punishing a physical consistency regularization term of a deviation between a spectrum generated by the physical model and a current end member spectrum based on a differentiable radiation transfer model; solving the objective function to obtain a final end member spectrum and an abundance matrix corresponding to the end member spectrum; and identifying altered minerals by utilizing the final end member spectrum, and extracting mineral alteration characteristics of the to-be-processed region in combination with an abundance matrix corresponding to the end member spectrum. According to the method, the space-spectrum composite kernel function is introduced, the nonlinear unmixing problem is solved in the high-dimensional feature space, and the complex nonlinear mixing effect existing in the surface environment can be known.

The disclosure relates to an optical system comprising a laser source (1) which generates pulsed laser radiation consisting of a temporal sequence of laser pulses in an input laser beam (EL), a splitting element (2) which follows the laser source (1) in the course of the beam and splits each of the laser pulses into laser pulse replicas separated spatially and / or temporally from one another, a combination element (4) which follows the splitting element (2) in the course of the beam and superimposes the laser pulse replicas in a respective laser pulse in an output laser beam. It is the task of the disclosure to provide an improved optical system compared to the prior art. It should be possible to generate particularly short and thus spectrally broadband laser pulses of high power with the optical system. The disclosure proposes that at least one multipass cell (3) is arranged in the beam path between the splitting element (2) and the combination element (4), through which the laser pulse replicas propagate, wherein the multipass cell (3) contains a medium in which the laser pulse replicas undergo nonlinear spectral broadening.

The application discloses a Raman spectrum decoupling method based on a physical information neural network and belongs to the technical field of spectral quantitative analysis. The application firstly collects pure substance Raman spectra, constructs spectrum generation sub-modules of each pure substance by taking a peak function as a neuron; then prepares binary standard samples, constructs a binary mixture spectrum neural network model, and calibrates the relative correction coefficients of each component relative to a reference substance; then, a multi-component mixture spectrum neural network model is constructed, which is composed of parallel pure substance spectrum generation sub-modules and offset correction modules, and the total loss function is the weighted sum of the spectrum reconstruction loss and the content loss based on the relative correction coefficient for joint optimization training; when applied, the input is the Raman spectrum of the sample to be measured, the weight parameters are optimized and mapped into the concentration of each component. In the complex multi-component system with serious peak overlap and nonlinear spectral behavior, the application can realize stable and interpretable Raman spectrum decoupling and quantitative analysis.

The invention discloses an isotope analysis method based on cooperation of a nonlinear spectrum and a laser ablation technology, the isotope analysis method comprises a nonlinear spectrum detection module and a laser ablation module, the laser ablation module can ablate a solid sample to generate plasma, and in the nonlinear spectrum detection module, the laser ablation module is used for ablating the solid sample to generate plasma; the laser output by the wavelength tunable continuous laser is divided into three laser beams, two laser beams are reversely and collinearly transmitted, the other laser beam intersects with the other two laser beams at a small angle, the focuses of the three laser beams coincide in the plasma generated by the laser ablation module, the wavelength of the wavelength tunable continuous laser is scanned, the power of the three laser beams is repeatedly adjusted, and the laser ablation is completed. And recording signal intensities at different wavelengths to obtain a nonlinear spectrum, fitting the spectrum by using a Lorentz function, calculating a signal integral intensity ratio of different isotopes, carrying out root marking on the ratio to obtain an isotope abundance ratio, and calculating the isotope abundance ratio according to the isotopic abundance ratio. The problem that current solid sample isotope analysis needs a complex sample preparation process can be solved.

The application discloses a LIBS cross-instrument spectral library migration method and system based on spectral calibration and deep learning, and relates to the technical field of laser-induced breakdown spectroscopy (LIBS) analysis.The application aims at the technical problems that the existing LIBS cross-instrument calibration method cannot fit the nonlinear spectral difference between instruments, the spectral library multiplexing is poor, and the cross-device model deployment precision is low, and proposes a hybrid spectral calibration-deep spectral migration (HSH-DSM) framework, which realizes high-precision conversion of source domain LIBS spectrum to target domain LIBS spectrum through three core steps of physical guided spectral preprocessing, local intensity calibration and adjustable multi-layer perceptron (MLP) deep spectral migration.This method can realize LIBS spectral library cross-instrument multiplexing, greatly reduce the library building cost, and is suitable for LIBS cross-device detection scenes such as geological exploration, industrial detection, environmental monitoring and planetary exploration.

The invention provides a nano material / structure harmonic measurement-oriented nonlinear optical device and method, and relates to the technical field of optical systems. The device comprises a microscopic imaging light path for imaging samples such as nanometer materials and nanometer structures, and a nonlinear measurement light path for measuring harmonic waves of the samples. Compared with an existing optical system, the device has the advantages of being simple in design, capable of observing the surface morphology of the nanometer materials and the structures, high in expandability, good in stability and the like. According to the utility model, the nonlinear spectrum and nonlinear frequency conversion efficiency of a sample with the scale of hundreds of nanometers or several micrometers can be effectively measured by acquiring a sample image and a transmission nonlinear harmonic signal.

The present invention discloses a nonlinear spectral calibration method and system for a hyperspectral camera, comprising: S1: under any environmental parameter, collecting pixel brightness values ​​of a high-reflection area, a medium-reflection area, and a low-reflection area of ​​a multi-region standard material calibration plate as raw data; S2: constructing a correction lookup table, the correction lookup table containing fitting coefficients under different environments; S3: judging whether the environmental change value exceeds a threshold; if not, using the correction coefficient to calculate the error term; if exceeding the threshold, repeating S1, S2, and S3 to calibrate the fitting coefficient and calculate the error term under real-time environmental parameters; S4: obtaining the actual reflectivity based on the error term and preliminary reflectivity calculation; S5: calculating the wavelength offset, correcting the wavelength of the full spectrum based on the wavelength offset of the full spectrum, performing real-time compensation for the environmental parameters, and dynamically correcting the reflectivity calculation model based on environmental changes, thereby ensuring that the calibration process is not disturbed by environmental factors and remains stable.

The present invention provides a second harmonic characterization method, a characterization optical system based thereon, and a detection device. After selecting a scanning point on the surface of a sample to be detected, the second harmonic characterization method continuously tunes the wavelength of the fundamental frequency light from a first set wavelength to a second set wavelength by tuning the wavelength of the fundamental frequency light. After each tuning of the wavelength of the fundamental frequency light, the fundamental frequency light with the tuned wavelength is incident on the scanning point, and the second harmonic signal generated by the wavelength-tuned fundamental frequency light is collected; then, based on the collected second harmonic signal, a nonlinear spectrum of the second harmonic signal is plotted. Through the nonlinear spectrum of the second harmonic signal, the different defect types, the defect energy levels of different defect types, and the fundamental frequency light wavelengths corresponding to different defect types of the scanning point during this scanning process can be obtained. The second harmonic is used to effectively characterize lower defect densities, and the relevant parameters of the sample to be detected can be extracted in a targeted manner, shortening the time spent extracting relevant device parameters.

The invention relates to an optical system comprising a laser source (1) generating pulsed laser radiation consisting of a temporal sequence of laser pulses and at least one pulse compression device (3) located in the beam path and having a nonlinear medium (7), wherein the laser pulses undergo a nonlinear spectral broadening during the propagation through the medium (7) and a chirp is applied to the laser pulses. The object of the invention is to provide an optical system which makes it possible to generate nonlinearly compressed laser pulses with an improved temporal pulse contrast or with an improved pulse quality. According to the invention, a group delay dispersion which varies along the beam path and at least partially compensates the chirp is applied to the laser pulses by the pulse compression device (3).

The scheme discloses a few-cycle pulse generation system and method based on pulse shaping, wherein: a superfast laser module is used to output a high-energy pulse laser, and the high-energy pulse laser is injected into a pulse shaping module; the pulse shaping module is used to determine a parabolic pulse waveform according to parameter configuration of a nonlinear spectral broadening module, and obtain a parabolic pulse with a steep time-domain front edge according to the parabolic pulse waveform; the nonlinear spectral broadening module is used to realize nonlinear spectral broadening, and obtain a spectral broadening pulse laser with approximate linear chirp; and a pulse compression module is used to perform dispersion compensation and pulse compression on the spectral broadening pulse laser, and obtain a target pulse laser with high energy and few cycles. The scheme can effectively solve the nonlinear chirp accumulation problem in the traditional Gaussian pulse post-compression scheme, can realize higher-quality pulse compression, thereby realizing high-energy few-cycle pulse laser transmission with a narrower pulse width, and further providing a high-performance driving light source for the generation of attosecond pulses.

The application relates to the technical field of ground object component analysis, and discloses a mineral alteration feature extraction method based on hyperspectrum, which comprises the following steps: obtaining hyperspectrum remote sensing image data of a region to be processed and performing atmospheric correction and noise reduction preprocessing; extracting initial end-member spectrum after the preprocessing; constructing a target function of nonlinear spectrum unmixing, wherein the target function comprises the following items: a data fidelity item, an abundance constraint item, a physical consistency regularization item for penalizing the deviation between the spectrum generated by a physical model and the current end-member spectrum based on a differentiable radiation transfer model; solving the target function to obtain the final end-member spectrum and an abundance matrix corresponding to the end-member spectrum; identifying alteration minerals by using the final end-member spectrum, and extracting the mineral alteration features of the region to be processed in combination with the abundance matrix corresponding to the end-member spectrum. The application can understand the complex nonlinear mixing effect existing in the surface environment by introducing a space-spectrum composite kernel function, and solving the nonlinear unmixing problem in a high-dimensional feature space.

The invention belongs to the field of remote sensing hyperspectral image processing, and provides a hyperspectral image waveband selection method based on a FATA evolutionary calculation method. A Kapur information entropy strategy and Jaffries-Matusita (JM) distance estimation are combined with a mirage evolutionary calculation method (FATA), and a wave band selection framework is designed. According to the frame, a three-dimensional spectral relationship representation space is constructed, and pixel-level information and waveband correlation in context are effectively captured; and secondly, the exponential calculation complexity of a traditional spectral relation evaluation method can be avoided by utilizing the characteristics of robust convergence and avoidance of falling into local optimum of FATA in a nonlinear spectral relation space, the optimal solution is obtained by comprehensively evaluating a wave band, and the processing efficiency is improved by reducing dimensions. The method has reliability, efficiency and stability in hyperspectral band selection, and supports subsequent classification tasks.