925 results about "Mid infrared" patented technology

The invention belongs to the technical field of alkane gas leakage detection, and particularly relates to a leaked gas detection method based on deep learning and an optical flow method. The method comprises the following steps: simulating image data of real gas leakage by using a Gaussian plume model, and making a data set; a deep learning network YOLOv8-seg model is used for training; an intermediate infrared camera is used for monitoring an area where leakage may occur; when leakage occurs, a leakage gas area is detected and segmented, and a binary segmentation mask of leakage gas is generated; and analyzing the motion direction of the gas plume in the binary segmentation mask by using an optical flow method. The problem that leakage points are difficult to find in an existing gas detection means is solved, the diffusion track of leaked gas can be tracked more accurately, and rapid tracing is achieved.

The invention provides a medium-wave infrared detection chip and system, the chip is composed of a plurality of detection units arranged in the same plane, each detection unit is composed of a substrate, a buffer layer, a lower contact layer, an absorption layer, a barrier layer and an upper contact layer in sequence, the chip is arranged based on an nBp type structure, the buffer layer, the lower contact layer, the absorption layer, the barrier layer and the upper contact layer are all of a multi-period stacked superlattice structure, the thickness, the number of layers and the doping concentration of the InAs doped layers and the GaSb doped layers which are stacked in each period are controlled, dark current suppression in the mid-infrared detection process is achieved, and the quantum efficiency is effectively improved.

An on-chip mid-infrared micro-ring resonant cavity microfluidic spectrometer is integrated on a substrate material and comprises a spot size converter, an optical coupler, a microfluidic module, a micro-ring resonant cavity, a miniature thin-film resistance heater, a sequential control power supply module, an optical filtering system and a photoelectric detector array. Selective filtering is performed on an input optical signal, and the flow and flow velocity of liquid or gas to be detected are controlled by using the microfluidic module, so that selective absorption of spectral components of the liquid or gas to be detected is realized. In addition, the invention also discloses a mid-infrared integrated optical chip micro-fluidic multiphase detection device comprising the spectrometer and a detection method thereof, the device also comprises a pumping and reference light source module and an on-chip mid-infrared frequency comb generation module, a broadband frequency comb is generated as a light source, a photoelectric detector array is used for collecting signals, and the detection precision is improved. The detection and inversion of the type and concentration of multi-component liquid or gas to be detected are realized, and the on-chip, real-time and micro detection of multi-component substances is realized.

The invention provides an eyeball tracking optical system and a display device. The eyeball tracking optical system comprises an infrared light emitting device, a first lens group and an infrared imaging device. Wherein the infrared light emitting device is used for emitting infrared light to human eyes; the first lens group is used for being arranged on the light emitting side of the display panel, the side, away from the display panel, of the first lens group is used for converging infrared light reflected by human eyes, and the side, close to the display panel, of the first lens group is used for diverging the infrared light deflected by the first lens group; the infrared imaging device is arranged on the side, close to the display panel, of the first lens set, and the imaging face of the infrared imaging device faces the first lens set. Infrared light reflected by human eyes is deflected after passing through the first lens group, and is incident to the infrared imaging device.

The invention discloses a high-power intermediate infrared fiber laser. The fiber laser is composed of a first pumping source, a second pumping source, a pumping beam combiner, a high-reflectivity fiber grating, a low erbium-doped fluoride fiber, a low-reflectivity fiber grating, a cladding light filter, a fiber end cap, a collimating lens and a dichroscope. The mode of combining erbium ion ground state transition achieved through fiber core pumping and erbium ion excited state transition achieved through cladding pumping is adopted, mid-infrared laser upper energy level particle number accumulation is obtained, and meanwhile laser lower energy level particles are effectively consumed through the cladding pumping transition process. And the population inversion state of the laser system is kept, and the particle circulation rate and the quantum efficiency from the pump light to the intermediate infrared laser are improved, so that the generation of high-power and high-efficiency intermediate infrared fiber laser is realized.

The invention relates to the technical field of refrigeration material preparation, in particular to an efficient passive radiation refrigeration material suitable for a sub-super environment and a preparation method and application of the efficient passive radiation refrigeration material. The method comprises the following steps: uniformly mixing thermoplastic polyurethane, sunlight high-reflection inorganic particles and a phase change material in a solvent; after a chemical foaming agent is added, the obtained suspension liquid is heated and foamed in a confinement mold, and wet gel is formed; and finally, carrying out freeze drying treatment to obtain the composite porous aerogel. The prepared material has a micro-nano porous skeleton formed by TPU, and inorganic particles and PCM are uniformly dispersed in the skeleton wall. Through component cooperation and a special porous structure, the material has extremely high sunlight reflectivity and mid-infrared emissivity, self-adaptive temperature regulation and control are achieved through PCM phase change, the problem that refrigeration of a traditional material fails in the sub-environment such as the vertical surface is effectively solved, and efficient sub-super-environment heat management is achieved.

The invention discloses an intermediate infrared polarization spectrum imaging method and device. The method comprises the following steps: carrying out joint coding on an intermediate infrared light beam carrying to-be-measured target space, spectrum and polarization information by adopting an intermediate infrared polarization spectrum modulator consisting of metasurface units which are arranged in an array and have non-correlation response characteristics; projecting the coding light field to a two-dimensional detector array to generate a two-dimensional coding image under single exposure; and decoding the two-dimensional coding image through a reconstruction unit so as to reconstruct and obtain a space-spectrum-polarization four-dimensional data cube of the target to be measured. The problem that polarization information cannot be rapidly obtained in the prior art is solved, target full information can be obtained under single exposure, and the system has the advantages of being high in imaging speed, simple in structure, easy to miniaturize and the like.

In various examples, infrared image data may be used to detect a subcutaneous characteristic(s) (e.g., a palm vein topology) of a person (e.g., a person requesting entry to a vehicle, a vehicle occupant) and authenticate the user based on the detected subcutaneous characteristic(s). For example, infrared image data representing one or more acquired subcutaneous characteristics (e.g., a topology of veins and / or other blood vessels in a region of the authenticating user's palm, hand, neck, forearm, face, fingertip, eye, etc.) may be generated. Hand and / or palm detection may be applied to detect a region depicting the user's hand or palm, and that region (or some subset thereof) may be segmented to generate a representation of an acquired vein topology. The acquired vein topology may be compared with one or more reference vein topologies stored in a database to determine whether the acquired vein topology matches one of the reference vein topologies.

The invention discloses a rolled piece temperature control system based on a steel rolling process, which relates to the technical field of steel rolling and comprises a detection module, a control module, an execution module and a cooling module, the detection module comprises infrared thermometer arrays, an ultrasonic thickness gauge, an electromagnetic flowmeter, a pressure transmitter and a thermal resistance thermometer, and the infrared thermometer arrays are used for being arranged in front of and behind a cooling section and respectively collecting initial temperatures before entering a cooling system. Through the self-adaptive PID algorithm, the finite difference heat conduction model and the Smith pre-estimation compensation strategy are combined, the problem of control delay caused by the large lag characteristic in the cooling process is solved, control parameters can be dynamically adjusted according to the rolling speed, the steel grade characteristic and the like, temperature adjustment better fits the actual working condition, and the control precision is improved. The phenomenon of supercooling or insufficient cooling in a traditional control mode is fundamentally avoided, and the uniformity and stability of the performance of rolled pieces are guaranteed.

The invention relates to the technical field of component analysis, in particular to an intermediate infrared spectrometer sensor verification system which comprises the following steps: acquiring spatial distribution information of a target sample through an automatic sampling module, and generating a corresponding first feature group based on the spatial distribution information; adjusting an emission wave band and a modulation strategy corresponding to a mid-infrared light source, converting mid-infrared photons into visible light signals, and generating a corresponding second feature group; performing down-sampling processing on the original spectral data to generate a corresponding third feature group; inputting the sparse spectral coefficient into a pre-trained deep learning reconstruction model, and dynamically correcting the reconstruction process in combination with an environment temperature compensation parameter to generate reconstructed spectral data corresponding to high resolution; and analyzing the reconstructed spectrum data, matching a preset substance spectrum database, extracting a characteristic absorption peak position and an intensity ratio of the target substance, and generating a corresponding final analysis result. According to the invention, the intelligence of the sensor verification system can be improved.

The invention relates to an intermediate infrared holmium-praseodymium-calcium-magnesium-zirconium co-doped gadolinium-gallium garnet laser crystal as well as a preparation method and application thereof, and belongs to the technical field of single crystals or uniform polycrystalline materials with certain structures. The mid-infrared holmium-praseodymium-calcium-magnesium-zirconium co-doped gadolinium-gallium garnet laser crystal comprises a host crystal, active ions, de-active ions and auxiliary ions, the host crystal is a gadolinium gallium garnet crystal, the activating ion is Ho < 3 + >, the deactivating ion is Pr < 3 + >, and the auxiliary ions at least comprise Ca < 2 + >, Mg < 2 + > and Zr < 4 + >; the doping concentration of Pr < 3 + > is greater than or equal to 0.05 at%. The mid-infrared holmium-praseodymium-calcium-magnesium-zirconium co-doped gadolinium-gallium garnet laser crystal has the advantages of low laser threshold and high laser output power and efficiency.

The invention discloses a high-tolerance synchronous dual-band pulse laser, and relates to the field of lasers, and the laser comprises a first resonant cavity and a second resonant cavity; the first resonant cavity comprises a first pumping source and an optical annular cavity formed by sequentially connecting a first wavelength division multiplexer, a first thulium-doped optical fiber, a first optical coupler, a first isolator, a second wavelength division multiplexer, a high-nonlinearity saturable absorber, a third wavelength division multiplexer and a first polarization controller; the second resonant cavity comprises a second pumping source and an optical annular cavity which is formed by sequentially connecting a fifth wavelength division multiplexer, a second erbium-doped fiber, a second optical coupler, a second wavelength division multiplexer, a high-nonlinearity saturable absorber, a third wavelength division multiplexer, an electric control adjustable delay line, a fourth wavelength division multiplexer, a second polarization controller and a second isolator, and the fifth wavelength division multiplexer, the second erbium-doped fiber, the second optical coupler, the high-nonlinearity saturable absorber, the third wavelength division multiplexer, the electric control adjustable delay line, the fourth wavelength division multiplexer, the second polarization controller and the second isolator; and the first optical coupler and the second optical coupler respectively output synchronization pulses in the wave bands of 2 microns and 1.5 microns. The device is compact in structure, low in manufacturing cost, convenient to operate and capable of covering the mid-infrared band of 2 microns.

The invention discloses an infrared photothermal imaging system and method in structured light illumination fluorescence detection, and belongs to the field of super-resolution imaging. The system comprises a structured light generation module, a fluorescence excitation module, a fluorescence collection module and a mid-infrared light thermal module. The structured light generation module generates structured light with adjustable phase and direction; the fluorescence excitation module inputs the structured light to a to-be-analyzed sample and excites the sample to emit fluorescence; meanwhile, infrared pulse laser can be input into a sample by utilizing a mid-infrared photothermal module, and the fluorescence intensity is modulated by utilizing a photothermal effect; finally, fluorescent light emitted by the sample is collected by a fluorescent light collecting module, and an infrared photothermal image in structured light illumination is obtained. The system breaks through the diffraction limit, the resolution ratio is increased by two times at most, the intrinsic infrared spectrum of the sample is obtained through mid-infrared photothermal imaging, and the chemical components and the structure of the sample are reflected. According to the invention, two technologies are combined, so that the intrinsic infrared spectrum information of the sample is provided under the sub-diffraction limit.

The invention discloses an edge enhancement imaging method based on nonlinear angle filtering, and the method comprises the following steps: S1, employing mid-infrared coherent light as signal light to vertically irradiate a to-be-imaged object from one side of the to-be-imaged object, enabling the signal light to pass through the to-be-imaged object, and carrying out the diffraction, and obtaining the angular spectrum component of the signal light; s2, a nonlinear crystal is placed on the side, away from the signal light, of the object to be imaged, and the angular spectrum component, obtained in the step S1, of the signal light is transmitted to the nonlinear crystal and collected by the nonlinear crystal; s3, pump light is loaded in the nonlinear crystal, frequency conversion is carried out on the angular spectrum meeting specific conditions, nonlinear angle filtering is achieved, and a conversion light signal is obtained; and S4, the converted light signals obtained in the step S3 are collected by an imaging system and are imaged, and edge detection of the image of the object to be imaged is realized.

The invention provides a holmium and ytterbium co-doped mid-infrared microsphere Raman laser and a preparation method thereof, and relates to the technical field of laser preparation, the holmium and ytterbium co-doped mid-infrared microsphere Raman laser comprises an infrared transmission optical fiber, a pump light source, holmium and ytterbium co-doped tellurate glass microspheres and passive tellurate glass microspheres, pump light emitted by the pump light source is guided to a conical region through the infrared transmission optical fiber, and the holmium and ytterbium co-doped tellurate glass microspheres and the passive tellurate glass microspheres are arranged in the conical region; sequentially carrying out optical coupling with holmium and ytterbium co-doped tellurate glass microspheres and passive tellurate glass microspheres; in the holmium and ytterbium co-doped tellurate glass microspheres, the doping amount of the holmium element is 0.3%, and the doping amount of the ytterbium element is 0.45% according to the mass percentage. Compared with the prior art, through the cascade structure of the holmium-ytterbium co-doped microspheres and the passive microspheres, three-step wavelength conversion of pump light-rare earth ion lasing-Raman frequency shift is realized in a single system for the first time, and the wavelength limitation that a traditional single microsphere depends on a rare earth ion fixed energy level is broken through.

The invention discloses an ultra-wide-band tunable intermediate infrared laser device and a light beam pointing stabilizing method. The device comprises a fundamental frequency pumping source, an ultra-wide tuning annular resonant cavity, a nonlinear frequency conversion crystal, a laser wavelength tuning controller and a light beam pointing stabilizing controller. The fundamental frequency pumping source is used for providing pumping laser for high-peak power pulse emission, the ultra-wide tuning annular resonant cavity adopts a special special-shaped angle design, a high-refractive-index intrinsic substrate is used as an input and output coupling mirror, and the pumping laser enters the high-refractive-index intrinsic substrate at a Bronsted angle and enters the resonant cavity through coupling of the high-refractive-index intrinsic substrate; at least two cavity mirrors in the resonant cavity mirror are gold mirrors highly reflecting near-infrared and middle-infrared bands, the pump light passes through the nonlinear frequency conversion crystal and forms a closed-loop light path in the resonant cavity, efficient optical parametric oscillation is achieved, and middle-infrared laser with an extremely wide wavelength tuning range is generated. And the light beam pointing stabilization controller controls the resonant cavity mirror to compensate light beam pointing deviation, so that continuous wavelength tuning is realized, and the light beam pointing is kept unchanged.

The invention belongs to the technical field of mid-infrared photoelectric detectors, and particularly relates to a mid-infrared photoelectric detector based on an ultra-thin metasurface and a preparation method thereof.The method comprises the steps that firstly, a substrate and an element atomic material are provided, an ellipsometry test is conducted to obtain dielectric functions of the substrate and the element atomic material, the dielectric functions serve as input to be substituted into finite element software, and the finite element software serves as the input to obtain the ultra-thin metasurface-based mid-infrared photoelectric detector; theoretical modeling design is carried out on the metasurface, the metasurface is manufactured after the appropriate metasurface size is obtained, then reflectivity and transmissivity tests under different polarizations are carried out on the metasurface through an ellipsometry test, a metal layer is deposited on the metasurface through a standard electron beam evaporation technology to serve as an electrode, and the metasurface is manufactured. And finally, a CO2 laser is selected to irradiate the metasurface in a photoelectric detection experiment. By optimizing the structure parameters and the material performance of the metasurface, middle and far infrared broadband absorption, efficient photo-thermal conversion and photoelectric response are achieved, and therefore the problems that in the prior art, the corresponding wavelength is short, devices are heavy, and the detection efficiency is insufficient are solved.

The invention provides a high-speed large-capacity intermediate infrared laser communication method and system based on an integrated waveguide, and is mainly used for solving the problems that when an existing space laser communication system adopts intermediate infrared band transmission, a frequency conversion scheme based on a block material is poor in phase matching, large in size, low in conversion efficiency, low in cost and the like. And the actual requirements of high-speed and large-capacity communication are difficult to meet. According to the high-speed large-capacity mid-infrared laser communication method based on the integrated waveguide, the first integrated waveguide is adopted to realize conversion from a near-infrared band to a mid-infrared band frequency comb, the wavelength division multiplexing technology is combined to maximize the channel capacity, and then the second integrated waveguide is adopted to restore a near-infrared band optical signal. The problems of insufficient capacity, generation of attenuation and loss, low rate and the like when near-infrared band optical signals are transmitted in an atmospheric channel are avoided, space laser communication with the rate of Tbps magnitude is realized, an optical field can be restrained in a micro-nano waveguide structure to the greatest extent, and the frequency conversion efficiency is improved.

The present application relates to a kind of on-chip photo-thermal gas sensor and on-chip photo-thermal gas sensor assembly, the refractive index of the upper waveguide material layer of sensor ridge waveguide layer is greater than the refractive index of lower waveguide material layer, can support TM mode pump light and TE mode probe light simultaneously. That is, both high absorption of pump light and weak influence of probe light on the gas to be measured are considered, and the detection accuracy of the gas is improved. Moreover, a simpler waveguide structure is used, and the waveguide preparation process is simple, and the waveguide loss is relatively low. Compared with the photo-thermal interference method in optical fiber sensing, the interaction between pump light and the gas to be measured is greatly improved, the length of the detection waveguide is greatly shortened while ensuring high sensitivity, and the device size can be reduced to micrometer level. In addition, the waveguide structure of the on-chip photo-thermal gas sensor disclosed in the present application is prepared from chalcogenide glass, which has more obvious advantages for gas detection in the mid-infrared waveband.

The embodiment of the invention provides near-to-eye display equipment and an eye movement tracking method. The near-to-eye display device comprises an optical waveguide, a light source assembly, an image acquisition unit and a processing unit, the optical waveguide comprises a plurality of first coupling-out structures, and the first coupling-out structures can be switched between a coupling-out state and a non-coupling-out state; the light source assembly is used for emitting infrared light towards the optical waveguide; the image acquisition unit is used for acquiring an eye image; the processing unit is electrically connected with the optical waveguide and the image acquisition unit, and is used for determining the position of a preset eye region according to the eye image; determining a target coupling-out structure in the plurality of first coupling-out structures according to the position of the eye preset area; the target coupling-out structure is controlled to be in a coupling-out state, so that the infrared light is coupled out of the target coupling-out structure to a pupil area of the eye; and determining the gazing direction of the eye according to the light spot formed by the infrared light in the image of the eye. The technical scheme of the embodiment of the invention aims to enlarge the eye movement tracking range, so that the infrared light is accurately transmitted to the pupil area of the eye, and the eye movement tracking precision is improved.

The invention discloses an infrared dual-band single-photon laser radar imaging system, and belongs to the field of laser radar detection. The system comprises an infrared dual-band light source, a beam splitter, a first delay line, a light splitting module, a transceiver module, a frequency up-conversion module, a photoelectric detector, a single-photon detector, a signal acquisition module and a signal processing module. The infrared dual-band light source generates near-infrared and intermediate-infrared pulse laser; near-infrared laser is used for near-infrared detection, frequency up-conversion pumping and initial signals after passing through a beam splitter, intermediate-infrared laser is used for intermediate-infrared detection, intermediate-infrared detection signal echoes are subjected to time domain gating and frequency up-conversion by near-infrared pumping signals and then injected into a single-photon detector together with near-infrared detection signal echoes through time division multiplexing, and the intermediate-infrared detection signal echoes and the near-infrared detection signal echoes are subjected to frequency up-conversion. And detection imaging is realized through signal acquisition and processing. According to the invention, the weak target detection imaging capability of the single-photon laser radar in environments of gas, strong background noise and the like can be improved, and the multi-band sensing capability of the radar on target characteristics is improved.

The invention provides a mid-infrared high-speed waveguide type modulator capable of being integrated on a chip and a design method, and belongs to the technical field of semiconductor optoelectronic devices, aiming at solving the problem that an existing mid-infrared modulator cannot consider high speed, low loss and on-chip integration compatibility at the same time. The modulator comprises an InP substrate, an epitaxial structure growing on the InP substrate and a traveling wave electrode structure prepared on the epitaxial structure. The epitaxial structure sequentially comprises an InP contact layer, an InAlAs lower light limiting layer, an InP / InGaAs lower waveguide layer, an asymmetric multi-quantum well structure, an InP / InGaAs upper waveguide layer, an InAlAs upper light limiting layer and a Cap layer from bottom to top. The design method comprises the steps of selecting a compatible material system, designing an asymmetric multi-quantum well structure, processing an epitaxial structure into a ridge waveguide structure, designing a traveling wave electrode and carrying out device characterization testing. The method is suitable for design and preparation of the middle-infrared band high-speed light modulation device.

The invention discloses a heterogeneous three-core anti-resonance optical fiber for transmission from visible light to intermediate infrared light, and belongs to the technical field of optical fiber communication. The heterogeneous three-core anti-resonance optical fiber comprises an outer cladding layer from outside to inside along the diameter of the optical fiber, a first inner cladding layer, a second inner cladding layer and a third inner cladding layer are arranged in the outer cladding layer, and a plurality of nesting pipe assemblies with the same structure are arranged in the first inner cladding layer, the second inner cladding layer and the third inner cladding layer at equal intervals in the circumferential direction. An upper air fiber core area, a lower left hollow fiber core area and a lower right air fiber core area are defined by the nesting pipe assembly. The upper air fiber core area, the lower left air fiber core area and the lower right air fiber core area respectively work in a 4m wave band, a 2m wave band and a 1m wave band, have extremely low limiting loss in the three working wave bands, and have good bending resistance performance at the same time.

The invention provides a biomass combustion in-situ measurement method based on spectrum and flame imaging. The biomass combustion in-situ measurement method comprises the following steps that a biomass sample is pretreated and conveyed to a dropper furnace combustion monitoring system through pneumatic conveying; preheating, and monitoring combustion parameters in real time through a temperature control system and a data acquisition system; the synchronous acquisition system is connected with the Fourier transform infrared spectrometer, the ICCD camera and the intermediate infrared camera; spectral information in a flame heat radiation (200 nm to 20 [mu] m) wave band is obtained, and free radical and smoke component images are collected; and finally, comprehensively processing and analyzing the data, and extracting key parameters such as temperature, radiation characteristics, component concentration and the like. According to the invention, multi-parameter in-situ synchronous measurement is realized, combustion surface temperature and radiation characteristics are accurately calculated in combination with an advanced algorithm, and free radical and flue gas component distribution is quantified through an imaging technology. An efficient and reliable technical means is provided for studying a biomass combustion mechanism, optimizing a combustion process and controlling pollution emission, and the biomass combustion device has important scientific research and application values.

The invention relates to the field of mid-infrared focal plane array spectral imagers, and discloses a mid-infrared focal plane array spectral imager and a spectral imaging method thereof.The mid-infrared focal plane array spectral imager comprises a focal plane array, the focal plane array comprises a plurality of pixels, and the pixels are arranged in the focal plane array. Wherein each pixel comprises a PIN heterojunction and a CdS layer arranged at the interface of the PIN heterojunction, and the imaging method comprises the following steps: carrying out spectrum training on each pixel in a focal plane array of the mid-infrared focal plane array spectrum imager, and establishing an independent spectrum model for each pixel so as to form a spectrum model cube; performing spectrum reconstruction on each pixel in the focal plane array based on the spectrum model cube; and combining the reconstructed spectrums of all the pixel points to generate a spectral imaging result. The invention solves the problem that the prior art lacks a spectral imager for the mid-infrared focal plane, and has the characteristics of low cost, chip and simple process.

The invention relates to the technical field of unmanned aerial vehicle load system image registration, in particular to an infrared image and SAR image registration fusion method in dynamic flight of an unmanned aerial vehicle. Comprising the following steps: measuring and calibrating a relationship between an infrared camera focal length and an infrared Y-direction field angle on the ground, recording the relationship between the field angle and the focal length as a file, and storing the file on a camera control panel; the camera control panel controls the movement of the infrared camera through a PID algorithm until the field angle of the single pixel of the infrared image is matched with the field angle of the single pixel of the SAR image; extracting different-source image descriptors, matching the different-source image descriptors, storing the projection relation of each pixel coordinate as a matrix C, and calling to complete registration; and calculating the local contrast and information entropy of the infrared image and the SAR image, dynamically adjusting the fusion proportion, and generating a registration fusion image. The method has the advantages that simple calibration on the ground is only needed; and after zooming, a registration algorithm is operated on an airborne computer, and the efficiency and accuracy of feature matching are improved in combination with a multi-scale descriptor.

A first pumping source and a second pumping source are combined through a pumping beam combiner and are coupled into an erbium-doped fluoride fiber and a high-reflectivity fiber bragg grating, and the erbium-doped fluoride fiber and a low-reflectivity fiber bragg grating form a laser resonant cavity. The intermediate infrared laser is output through the low-reflectivity fiber bragg grating, the cladding light filter and the optical fiber end cap; the high-reflectivity fiber bragg grating and the low-reflectivity fiber bragg grating have the same grating period, the fourth-order harmonic reflection wavelength of the grating is located in the emission spectrum range of transition of erbium ions from the 4F9 / 2 energy level to the 4I9 / 2 energy level, and the fifth-order harmonic reflection wavelength of the grating is located in the emission spectrum range of transition of erbium ions from the 4I11 / 2 energy level to the 4I13 / 2 energy level; by adjusting the power of the first pumping source and the second pumping source, the net gain of laser transitions from the 4F9 / 2 energy level to the 4I9 / 2 energy level and transitions from the 4I11 / 2 energy level to the 4I13 / 2 energy level is regulated and controlled, and switching of laser working wavelengths is achieved.

The invention discloses an ultrafast heat switching device and a design method thereof. The ultrafast heat switch device comprises a first polariton layer, a fixed near-field gap and a second polariton layer which are sequentially arranged from top to bottom. According to the design method, an external ultrafast light pulse is utilized to excite a first polariton layer, and mid-infrared transient polaritons are generated. Time-varying coupling occurs between the transient polaritons and polaritons of the second polariton layer, opening or closing of a near-field thermal radiation channel is dynamically controlled, and a thermal switch function is realized. Based on the synergistic effect of heterostructure terminal pairing and transient polaritons, the picosecond-level response speed and the switch ratio exceeding four orders of magnitude are achieved. Under the optimal design, the device can achieve the laser cooling effect on the emitting electrode in a single switching period, and an innovative solution is provided for nanoscale dynamic thermal management.

The invention discloses a mid-infrared light detector and a preparation method thereof, and belongs to the technical field of light detection.The light detector comprises a piezoelectric substrate, and a Van der Waals heterojunction, an input interdigital transducer and an output interdigital transducer are arranged on the piezoelectric substrate; the input interdigital transducer and the output interdigital transducer are symmetrically arranged on two sides of the Van der Waals heterojunction; the input interdigital transducer is used for generating a surface acoustic wave according to the alternating current signal; and the output interdigital transducer is used for receiving the surface acoustic wave signal passing through the Van der Waals heterojunction and outputting the signal. According to the device, a periodic strain field and a piezoelectric field are formed on the surface of a substrate through surface acoustic waves, graphene plasmons are excited, mid-infrared light absorption is enhanced, photo-generated electron-hole space separation is promoted, photo-generated carrier recombination is inhibited, a photoelectric response signal is converted into an acoustoelectric signal, and the photoelectric response signal is converted into an acousto-electric signal. And high-performance mid-infrared light detection is realized by using the high-sensitivity response characteristic of the surface acoustic wave device to acoustoelectric interaction.

Techniques for low power gunshot sensor testing are disclosed. An acoustic generator and an infrared generator are disposed in a housing. The housing encompasses the acoustic generator and the infrared generator. The housing covers the gunshot sensor. The acoustic generator and the infrared generator are used for testing a gunshot sensor. The infrared generator and the acoustic generator are coupled to an activation circuit. A switch is coupled to the acoustic generator and the infrared generator. The switch provides activation control of the acoustic generator and the infrared generator. The infrared generator includes a light source operating in the near-infrared (NIR) band. The light source operating in the NIR band provides testing for a gunshot muzzle flash sensor. The infrared generator includes a light source operating in the mid-infrared (MIR) band. The light source operating in the MIR band provides testing for a passive infrared (PIR) sensor.