25 results about "Spectral purity" patented technology

The invention provides a thulium-doped optical fiber with high spectral purity and a preparation method thereof, and the thulium-doped optical fiber with high spectral purity adopts a profile design that the refractive index of a main gain layer follows linear gradual change distribution of a linear function and the refractive index of a secondary gain layer is constant, so that the mode distribution of an optical fiber fundamental mode is precisely overlapped with the main gain layer; the secondary gain layer is located at the lowest point of the waveguide refractive index; the design can effectively solve the problem that in the prior art, due to the limitation of the MCVD technology, the doping concentration difference of the main gain layer and the secondary gain layer is caused, and then the optimal emission wavelengths of different gain areas are inconsistent. Besides, depending on the bending loss difference of the main gain layer and the secondary gain layer, on the premise that the gain efficiency of the optical fiber is not sacrificed, effective separation of emission wavelengths of the main gain layer and the secondary gain layer can be achieved through bending regulation, the target wavelength of the main gain layer is reserved, and the non-target wavelength of the secondary gain layer is filtered out. And finally, the spectral purity of the thulium-doped optical fiber is improved.

The application provides a semiconductor structure and a preparation method thereof and a semiconductor laser, and relates to the field of lasers. The semiconductor structure comprises a substrate, a first waveguide layer, a resonant structure and a second waveguide layer; the first waveguide layer is arranged on the surface of the substrate along the thickness direction; the resonant structure comprises an active region, an input layer and an output layer; the active region, the input layer and the output layer are arranged on the side of the first waveguide layer away from the substrate; in a plane parallel to the plane in which the substrate is located, the input layer and the output layer are located on the two sides of the active region, and the output layer is arranged obliquely; in the direction away from the substrate, the output layer is away from the input layer; the second waveguide layer is arranged on the side of the resonant structure away from the surface of the first waveguide layer, and the second waveguide layer is connected with the resonant structure. The application can reduce the possibility of interference effect between reflected light and the light field in the FP cavity, make the longitudinal mode output of the semiconductor structure more stable, and improve the spectral purity of the semiconductor structure.

The application discloses a LiNbO3-based periodic curved three-busbar structure acoustic wave resonator and a preparation method thereof, which comprises a substrate, a piezoelectric film layer arranged on the substrate, an interdigital electrode layer arranged on the piezoelectric film layer, a release hole arranged on the piezoelectric film layer, and a cavity arranged in the substrate, wherein the interdigital electrode layer is provided with symmetrically arranged interdigital electrodes, and two interdigital electrodes on the same side are connected by three parallel periodic curved busbars. The transverse excitation bulk acoustic resonator (XBAR) based on the curved three-busbar structure can effectively suppress the transverse high-order stray mode, significantly weaken the ripple in the passband, suppress the additional acoustic energy loss caused by the parasitic mode, improve the flatness and stability of the frequency response, and improve the signal transmission performance of the device. Compared with the traditional XBAR with the parallel busbar structure, the structure can effectively avoid the excitation of other non-target acoustic modes during the resonance process, thereby improving the spectral purity of the device and increasing the Q value by about 4 times compared with the traditional XBAR.

The invention relates to a polarization entangled photon pair, in particular to a polarization entangled photon pair generation method and device based on a mixed framework, and the method comprises the steps: bidirectional excitation: a dual-wavelength polarization beam splitter (PBS) divides laser into two beams of light which are horizontally and vertically polarized, and the two beams of light are transmitted in the clockwise CW direction and the anticlockwise CCW direction of a Sagnac interference ring respectively; photon pair generation: the two beams of light are coupled into a waveguide, and in the waveguide, horizontal polarized light propagating along the clockwise CW direction and vertical polarized light propagating along the anticlockwise CCW direction respectively generate a pair of photon pairs; quantum interference and entanglement generation: after the two paths of photon pairs are output from the waveguide, the two paths of photon pairs converge at a dual-wavelength polarization beam splitter (PBS) again, the amplitudes of the two paths of photon pairs are coherently superposed by regulating and controlling the phase in a Sagnac interference ring, and an ideal polarization entanglement singlet state is generated at two output ports of the dual-wavelength polarization beam splitter (PBS); according to the invention, the defect that high brightness, high efficiency, high entanglement fidelity, high spectral purity and high photon indistinguishability cannot be synchronously realized can be effectively overcome.

The invention discloses a photo-production microwave method based on a light injection semiconductor laser. An output optical signal of injecting the light in the single-period oscillation state into the semiconductor laser is transmitted through an optical fiber to generate an electric feedback signal, the electric feedback signal is used for performing electro-optical modulation on the injected light, and finally, the output optical signal is subjected to photoelectric detection to obtain a low-noise photo-generated microwave signal; the electric feedback signal generation method comprises the following steps: firstly, converting a transmitted output optical signal into an electric signal and dividing the electric signal into two paths; performing frequency division on the first electric signal to obtain a frequency-divided electric signal; performing feedback control adjustment on the phase of the second path of electric signal by taking the constant phase difference between the frequency division electric signal and a reference signal with the same frequency as a control target; and combining the second path of electric signal after feedback control adjustment with the reference signal into one path to obtain the electric feedback signal. The invention further discloses a photo-generated microwave device based on the light injection semiconductor laser. The frequency spectrum purity and the frequency stability of the signal can be effectively improved.

A reflective spectral purity filter (SPF) for extreme ultraviolet (EUV) light includes a substrate having a reflective surface and an angle of incidence of at least 60 degrees, and a blazed diffraction grating formed on the substrate, the blazed diffraction grating having a grating pitch and blaze angle (fixed or variable) configured to simultaneously diffract incident EUV light into a higher-order diffraction angle and confine out-of-band (OOB) light to a Oth order reflection angle to angularly separate the EUV light and the OOB light. An imaging system including the reflective SPF, the imaging system having a field of view (FOV) configured to collect the spatially filtered EUV light and reject the OOB light based on angular separation of the lights.

The invention relates to the technical field of lasers, in particular to a semiconductor laser which comprises a first laser module, a first light beam conversion lens, a first slow axis conversion lens, a first volume Bragg grating and a half-wave plate which are sequentially arranged along a first light beam path. The second laser module, the second light beam conversion lens, the second slow axis conversion lens and the second volume Bragg grating are sequentially arranged along a second light beam path; the polarization splitting prism is located at the intersection point of the first light beam path and the second light beam path; the third volume Bragg grating is located on the side, away from the half-wave plate, of the polarization splitting prism; wherein the diffraction efficiency of the first volume Bragg grating is lower than that of the third volume Bragg grating, and the central wavelength of the first volume Bragg grating is the same as that of the third volume Bragg grating. According to the invention, the multi-mode resonance effect can be suppressed, the side-mode suppression ratio can be improved, and the spectral purity after the line width is narrowed can be improved.

The invention discloses a control method of a multi-piezoelectric ceramic vibration exciter parallel combination system, and relates to the technical field of vibration control and piezoelectric driving, and the method comprises the steps: synchronously collecting the working time sequence waveform of each vibration exciter and the energy consumption flow data of the system, calibrating the waveform, and carrying out the spectrum purity analysis of the energy consumption data to extract the fundamental wave and harmonic wave components. And performing time-frequency domain alignment fusion on the calibrated time sequence waveform and the energy consumption spectrum component, and constructing a system state fusion tensor. And based on the tensor, identifying phase coherence and energy coupling strength among excitation units in the system, and further deducing a global vibration mode and a local instability risk area of the system. And making a dynamic balance control plan according to a deduction result, redistributing output energy of each vibration exciter and coordinating action phases of the vibration exciters. According to the invention, accurate diagnosis and risk prediction of the internal interaction state of the parallel vibration exciter system are realized, and the stability and controllability of cooperative work of the system are improved.

The invention relates to the technical field of semiconductor lasers, in particular to an electric control high-speed tunable laser based on a spiral lithium niobate waveguide. The substrate opening is formed in the upper end surface of the substrate; the gain chip is arranged in the opening of the substrate; the lithium niobate film optical waveguide is arranged on the upper end surface of the substrate; the device further comprises a collimating lens, an optical etalon and a reflector. The collimating lens, the optical etalon and the reflector are sequentially arranged on the right side of the laser output end of the lithium niobate film optical waveguide in the laser output direction. The invention has the following beneficial effects: 1, high-speed electric control tuning; 2, the adjusting range is wide; 3, compact integrated design; 4, the spectral purity is high.

The invention discloses an ultra-narrow linewidth continuous wave low-noise fiber seed laser generation system. The system comprises a semiconductor pumping source, a single-mode wavelength division multiplexer, a phase shift Bragg fiber grating, a polarization-maintaining fiber circulator, a scattering fiber, a polarization-maintaining tunable fiber grating, a polarization-maintaining isolator, a dispersion compensation fiber, a semiconductor optical amplifier and a polarization-maintaining 12 fiber coupler. The system generates single-frequency laser through the phase shift Bragg fiber grating, realizes line width narrowing by combining distributed Bragg feedback based on Rayleigh scattering, improves output power by using the semiconductor optical amplifier, and effectively suppresses noise by combining the dispersion compensation fiber. According to the scheme, the ultra-narrow linewidth continuous wave low-noise optical fiber seed laser with high stability and high spectral purity can be realized, and the ultra-narrow linewidth continuous wave low-noise optical fiber seed laser has important application value, is suitable for a front-end light source of a high-quality optical fiber laser, and provides key support for the fields of precision measurement, coherent communication and the like.

Techniques disclosed herein relate to photon sources with high spectral purity and high brightness. In one embodiment, a photon-pair source includes a pump waveguide, a first resonator coupled to the pump waveguide to couple pump photons from the pump waveguide into the first resonator, a second resonator coupled to the first resonator, and an output waveguide coupled to the second resonator. The second resonator is configured to convert the pump photons into photon pairs. The second resonator and the first resonator are configured to cause a coupling-induced resonance splitting in the second resonator or the first resonator. The second resonator and the output waveguide are configured to couple the photon pairs from the second resonator into the output waveguide. In some embodiments, the photo-pair source includes one or more tuners for tuning at least one of the first resonator or the second resonator.

The utility model discloses a backlight module and electronic equipment, and the backlight module comprises a light guide plate layer which comprises a light guide plate; the light source layer is arranged below the light guide plate layer; and the quantum dot film layer is arranged above the light guide plate layer. The backlight module provided by the embodiment of the utility model is higher in spectral purity.

The invention discloses a hyperspectral image unmixing method for double-end-member set non-negative tensor decomposition based on space structure maintenance, and belongs to the technical field of hyperspectral remote sensing image analysis. The method mainly comprises the following steps of: approximately representing hyperspectral image data as a product of an end member matrix and an abundance matrix and then adding a noise tensor; under the condition of a fixed end member matrix, a self-adaptive Sobel weighted space regular term is introduced for the abundance matrix, and the abundance matrix is iteratively updated through gradient weighting coefficients in the horizontal and vertical directions; and under the condition of a fixed abundance matrix, introducing truncation type low-rank-sparse constraint to the decomposed end member matrix, and alternately optimizing and updating the pure end member matrix and the variant component matrix by adopting an iterative reweighting strategy. According to the method, the continuity of a space structure is kept during unmixing, and meanwhile, a pure part and a variation part of an end member can be separated, so that the spectral purity, the physical interpretability and the anti-noise capability of an unmixing result are improved.

The invention provides a semiconductor structure, a preparation method thereof and a semiconductor laser, and relates to the field of lasers. The semiconductor structure comprises a substrate, a first waveguide layer, a resonant structure and a second waveguide layer. The first waveguide layer is arranged on the surface of the substrate in the thickness direction; the resonant structure comprises an active region, an input layer and an output layer, and the active region, the input layer and the output layer are arranged on the side, away from the substrate, of the first waveguide layer; in a plane parallel to the substrate, the input layer and the output layer are positioned on two sides of the active region, the output layer is obliquely arranged, and the output layer is far away from the input layer in a direction far away from the substrate; the second waveguide layer is arranged on the resonant structure away from the first waveguide surface and is connected with the resonant structure. According to the semiconductor structure, the possibility of generating an interference effect between reflected light and a light field in an FP cavity can be reduced, so that the longitudinal mode output of the semiconductor structure is more stable, and the spectral purity of the half-layer conductor structure is improved.

The invention relates to a source (1) for generating squeezed states for Gaussian boson sampling, comprising a laser (2), an optical component (3) and a waveguide (4), wherein the laser (2) is optically connected to the optical component (3) for transmitting the laser beam emitted by the laser, the optical component (3) is optically connected to the waveguide (4) for transmitting the laser beam, wherein the optical component (3) is configured to couple the laser beam into the waveguide (4) such that a spatial mode of order ≥ 1 is excited in the waveguide (4), and the waveguide (4) has a nonlinear medium, such that a squeezed signal-idler state having signal and idler beams is generated in the waveguide (4) with the spatial mode.In this way, a source for generating squeezed states for Gaussian boson sampling with improved spectral purity and brightness is provided.

A reflective spectral purity filter (SPF) for extreme ultraviolet (EUV) light includes a substrate having a reflective surface and an angle of incidence of at least 60 degrees, and a blazed diffraction grating formed on the substrate, the blazed diffraction grating having a grating pitch and blaze angle (fixed or variable) configured to simultaneously diffract incident EUV light into a higher-order diffraction angle and confine out-of-band (OOB) light to a 0th order reflection angle to angularly separate the EUV light and the OOB light. An imaging system including the reflective SPF, the imaging system having a field of view (FOV) configured to collect the spatially filtered EUV light and reject the OOB light based on angular separation of the lights.

This invention proposes a narrow-emission ultraviolet gallium sulfide quantum dot material and its synthesis method, belonging to the field of semiconductor quantum dot material technology. The method employs a one-pot synthesis strategy and introduces a specific passivating agent into the reaction system. By precisely controlling the reaction conditions and the amount of passivating agent, high-purity ultraviolet-emitting gallium sulfide quantum dots with an emission peak at 392 nm and a half-maximum width at half-maximum (HWHM) of 34 nm were successfully prepared. This synthesis method significantly reduces the HWHM of gallium sulfide quantum dots and improves their spectral purity. This invention provides an effective method for preparing ultraviolet environmentally friendly quantum dots with high color purity, demonstrating great application potential in cutting-edge fields such as lighting and full-color displays.

The application relates to the technical field of lasers, in particular to a semiconductor laser, which comprises a first laser module, a first light beam conversion lens, a first slow-axis conversion lens, a first volume Bragg grating and a half-wave plate arranged in sequence along a first light beam path; a second laser module, a second light beam conversion lens, a second slow-axis conversion lens and a second volume Bragg grating arranged in sequence along a second light beam path; a polarization beam splitter prism located at the intersection of the first light beam path and the second light beam path; and a third volume Bragg grating located on the side of the polarization beam splitter prism away from the half-wave plate; wherein the diffraction efficiency of the first volume Bragg grating is lower than that of the third volume Bragg grating, and the central wavelength of the first volume Bragg grating is the same as that of the third volume Bragg grating. The application is at least beneficial to inhibiting multimode resonance effect, improving the side mode suppression ratio and improving the spectral purity after line width narrowing.

This invention discloses a hyperspectral imaging detection system for marine plankton, belonging to the field of spectral detection technology, to solve the problem of poor spectral classification and recognition in aquatic environments. The invention achieves precise alignment between images and disturbances by simultaneously acquiring hyperspectral images and environmental disturbance parameters, and constructing a disturbance mapping sequence. A disturbance contribution weight matrix is ​​constructed based on the dominant band, and pixel-level spectral stripping is performed to extract the plankton purification spectrum, improving spectral purity and recognition accuracy. Furthermore, by combining derivative spectrum changes and image texture features, abnormal spectral drift regions are accurately identified. The coupling relationship between drift regions and background disturbances is further established to generate a dynamic interference factor map, dynamically adjusting the recognition model parameters, thus improving the system's recognition stability and classification accuracy in complex disturbance environments, making it suitable for multi-scenario marine ecological monitoring.

The invention relates to the technical field of laser control, in particular to a repetition frequency adjustable fiber laser which comprises a mode-locked laser light path and a spatial light path adjusting module, the spatial light path adjusting module is arranged in the mode-locked laser light path, and the spatial light path adjusting module comprises a piezoelectric ceramic assembly and an electro-optical modulator assembly. The piezoelectric ceramic assembly and the electro-optical modulator assembly achieve locking of the repetition frequency of the fiber laser through voltage cooperative adjustment, the repetition frequency is adjusted from the two dimensions of the physical cavity length and the equivalent cavity length, the fiber laser outputs laser meeting the preset repetition frequency, the all-fiber structure of a linear part is kept, and the optical fiber laser has the advantages of being simple in structure and convenient to use. According to the invention, the device is simple in structure, retains the functions of filtering and dispersion compensation, improves the spectral purity, pulse stability and locking precision of the output laser, avoids the additional loss and polarization disturbance, reduces the overall size of the laser, and covers the frequency demands of different scenes under high precision and wide range.

This invention discloses a method, system, and device for hyperspectral anomaly detection based on a multi-scale grid window, belonging to the field of hyperspectral image processing technology. The method includes: acquiring a hyperspectral image; constructing a spectral gradient tensor to calculate a multi-scale spectral abrupt change intensity map and determining the optimal window size; extracting heterogeneous spectral core regions; filtering pure background regions through spectral clustering and correcting the generalized likelihood ratio statistic to obtain anomaly scores; constructing an attention weight map to generate a multi-scale enhanced anomaly score map and calculating saliency weights for fusion; optimizing spatial consistency through a Markov random field and combining historical data with dynamic thresholds to output the detection results. This invention solves the problems of local contrast calculation being affected by multiple anomalies, background estimation ignoring spectral purity and spatial correlation, and poor detection robustness due to lack of historical time-series data utilization. It achieves accurate hyperspectral anomaly identification from coarse localization to fine detection, and from single-frame analysis to historical verification.

The present invention relates to a beam line system and method for spectral purification and effect verification thereof, comprising: an upstream radiation source interface for receiving broad spectrum radiation; the bunch transmission channel is used for limiting a radiation propagation path; the switchable spectrum blocking verification assembly can be switched between a first working state in which the switchable spectrum blocking verification assembly is inserted into the radiation propagation path and a second working state in which the switchable spectrum blocking verification assembly is moved out of the radiation propagation path, and is used for regulating and controlling radiation entering a subsequent structure under different spectrum conditions; the spectrum selection and purification assembly is used for carrying out selective transmission and spectrum purification on radiation of a specific target wave band; and the downstream detection unit is used for receiving and detecting the radiation treated by the spectrum selection and purification assembly. The beneficial effects of the invention are that through the combination of the double-reflector spectrum selection system and the narrowband filter membrane assembly, the multi-stage selection of the radiation of the specific target wave band is realized, and the spectral purity of the radiation of the target wave band can be improved.

The application discloses a hyperspectral anomaly detection method, system and equipment based on a multi-scale grid window, belongs to the technical field of hyperspectral image processing, and comprises the following steps: acquiring a hyperspectral image, constructing a spectral gradient tensor to calculate a multi-scale spectral mutation intensity graph, determining an optimal window size, extracting a heterogeneous spectral core area, screening a pure background area through spectral clustering and correcting a generalized likelihood ratio statistic to obtain an anomaly score, constructing an attention weight graph to generate a multi-scale enhanced anomaly score graph, calculating a saliency weight for fusion, optimizing spatial consistency through a Markov random field, and combining historical data dynamic threshold to output a detection result. The application solves the problems that local contrast calculation is interfered by multiple anomalies, background estimation ignores spectral purity and spatial correlation, and lack of historical time series data utilization leads to poor detection robustness, realizes precise hyperspectral anomaly recognition from coarse positioning to fine detection, and from single frame analysis to historical verification.

This invention discloses a monolithically integrated terahertz wave generation device and method, belonging to the field of optoelectronic technology. The device is a monolithically integrated structure, with a laser module, a Y-type beam combiner module, and a semiconductor optical amplifier sequentially integrated along the waveguide transmission direction. The laser module includes multiple parallel distributed feedback laser units. The Y-type beam combiner module couples the multiple distributed feedback laser units into a single waveguide. From bottom to top, the device includes a lower electrode, a substrate, a buffer layer, a high-refractive-index mode extension layer, a lower confinement layer, a multi-quantum-well active layer, an upper confinement layer, a transition layer, a grating, a ridge waveguide, and an upper electrode. The refractive index of the high-refractive-index mode extension layer material is higher than that of the buffer layer material. This invention has advantages such as a wide frequency tuning range, high power, and high spectral purity.