24 results about "Local field enhancement" patented technology

The invention belongs to the technical field of terahertz detection, and discloses a terahertz metamaterial enhanced spectrum detection system. Comprising the following steps: constructing a metamaterial enhancement factor tensor matrix according to the interaction between terahertz waves and a metamaterial; performing local field enhancement and surface plasma resonance optimization on the target sample based on the metamaterial enhancement factor tensor matrix to obtain a feature enhancement spectroscopy mapping function; constructing a multi-dimensional detection feature space based on a feature enhancement spectroscopy mapping function; a spectral signal enhancement topology network is formed based on the multi-dimensional detection feature space; enhancing the topological network based on the spectral signal, and generating an enhanced spectral feature discrimination function; obtaining a high-precision terahertz spectrum detection result based on the enhanced spectrum characteristic discrimination function; according to the invention, internal correlation between spectral characteristics can be mined, and comprehensive description of sample information is enhanced, so that high-precision terahertz spectrum detection is realized.

The invention discloses a method and a device for in-situ excitation of plasma in a high-temperature and high-pressure medium, at least one electrode is provided, the surface of the electrode is provided with a micro-nano structure with a tip enhancement effect, and the micro-nano structure is used for improving a local field enhancement factor on the surface of the electrode; placing the electrode in a reaction container filled with an aqueous solution; voltage is applied to the electrode through the power supply, the micro-nano structure generates a local high electric field at the tip of the micro-nano structure under the voltage, electron tunneling emission is caused, liquid phase discharge is triggered, and discharge plasma is generated. Through the electrode with the micro-nano structure on the surface, a local field enhancement factor is improved, so that the electrode can trigger liquid phase discharge under a relatively low potential. Resonance driving or three-phase alternating current input is adopted, and the self-adaptive tuning technology that the dielectric constant of an aqueous solution changes along with temperature and pressure is combined, so that efficient excitation of plasmas in a container is achieved. The method does not need an external heating device, is low in energy consumption and quick in response, and is particularly suitable for efficient heat management in a space limited or linear pipeline heat transfer scene.

The invention discloses a terahertz detector based on a circular metasurface and graphene composite structure and a method, and belongs to the technical field of semiconductor devices and micro-nano machining. The device comprises a substrate, a graphene layer, a circular metasurface layer, a first electrode and a second electrode, the graphene layer is arranged on the substrate; the first electrode and the second electrode are oppositely arranged on two side ends of the graphene layer; the circular metasurface layer is arranged on the graphene layer and located between the first electrode and the second electrode. According to the invention, the local field enhancement effect of the metasurface structure is combined with the photoelectric response of graphene, the frequency selective absorption of terahertz waves is realized, the signal-to-noise ratio and selectivity of the detector are improved, and the sensitivity and response speed of the detector are improved at the same time.

The application discloses a 200kV direct-current type high-voltage photoelectron gun, wherein a cathode electrode and an anode electrode adopt a multi-section curved surface structure design, and the front surface structures are symmetrically distributed, so that the risk of vacuum breakdown caused by local field enhancement of the direct-current high-voltage electron gun is reduced; a displacement adjusting structure is installed on the anode electrode, so that the distance between the anode electrode and the cathode electrode can be adjusted, and then the working voltage of the electron gun can be adjusted within 50-200kV; a photocathode transfer device is installed in the cathode electrode, and is used for replacing different types of photocathodes or damaged photocathodes; meanwhile, transmission and reflection type two photocathode working modes are arranged, and in the reflection type working mode, a detection laser can realize 15° and 45° two angle incidences, so that the direct-current type high-voltage electron gun has higher expansibility, and can be expanded to more application fields.

The invention discloses a method for measuring local field intensity and quantum yield in a plasmon-exciton coupling system, and belongs to the technical field of optical detection. The method comprises the following steps: preparing a plasmon-exciton coupling system sample consisting of a single gold nanoparticle and a single quantum dot probe and a single quantum dot reference sample which is not coupled with the gold nanoparticle; respectively measuring photoluminescence characteristics of the two samples under a fixed weak excitation condition by using a laser confocal microscope system to obtain photoluminescence tracks and second-order correlation functions corresponding to the two samples; counting the bright state intensity of the photoluminescence track and calculating the zero point value of the second-order correlation function; and the local field intensity and the exciton quantum yield are determined by comparing statistical results of the bright state intensities of the two samples and the zero value of the second-order correlation function. According to the method, a quantitative model between local field enhancement and plasma-exciton interaction is established, and the method plays an important role in plasmon nano sensing, plasmon laser, plasmon enhancement nonlinear effect and strong field nano optics.

According to the detection imaging system and application provided by the invention, the optical antenna-based ultra-wide spectrum imaging detection assembly is deployed on the focal plane, so that the optical transmission loss is greatly reduced, ultra-wide spectrum detection is realized by virtue of the broadband characteristic of the optical antenna, and the system architecture is effectively simplified. Through a unique spectrum conversion mechanism, the spectrum limitation of a traditional detector is broken through, a local field enhancement technology is matched, and the detection sensitivity of low-energy incident light is remarkably improved. Meanwhile, due to fine coupling of the optical antenna-based ultra-wide spectrum imaging detection assembly and the CMOS photosensitive array, efficient point-to-point energy transmission can be achieved, so that the rapid response characteristic and the high-speed frame frequency are organically combined, real-time dynamic imaging and data processing are supported, and finally the obvious advantages of wide spectrum coverage, high sensitivity, rapid response and low cost are shown.

The invention discloses a near-field terahertz nonlinear optical effect excitation detection method and system. A femtosecond laser space-time shaping technology is combined, a strong terahertz pulse is generated based on a femtosecond laser filament, the strong terahertz pulse is coupled with a tapping mode atomic force microscope, and space-time matching of probe vibration and the terahertz pulse is accurately controlled by using a synchronous sampling method, so that the time-space matching of the probe vibration and the terahertz pulse is realized. Mismatch between the low-repetition-frequency strong-field terahertz pulse and the vibration frequency of the near-field microscope probe is overcome, and strong-field terahertz near-field coupling and detection are achieved. The local field enhancement effect of the tip of the nanoprobe can realize nanoscale focusing (peak field intensity reaches MV / cm magnitude) of a terahertz field at a probe-sample gap, the near-field nonlinear interaction is remarkably enhanced, the diffraction limit is broken through, and the nanoscale spatial resolution is realized. According to the method, the excitation detection efficiency and the spatial resolution of the terahertz nonlinear effect are remarkably improved, and accurate excitation, characterization and regulation of the nonlinear optical effect of the sample can be realized.

This invention discloses a hydrogen sensing probe and its fabrication method. The nanowire array of this invention provides a high specific surface area and a three-dimensional channel structure, improving the contact efficiency between the sensitive layer and hydrogen, providing a pathway for light / gas transmission, and balancing sensitivity and response / recovery kinetics. At the same time, it abandons the traditional external cavity mirror structure. The Fabry-Perot interferometer cavity formed by the second and first reflective layers enhances the round-trip interaction between light and the sensitive layer, improves the spectral drift amplitude and signal-to-noise ratio, and reduces the influence of environmental factors. Furthermore, the nanowire array is coupled with the emitted light field and / or reflected light field at the end face to form a local field enhancement effect, which is superimposed with the Fabry-Perot interferometer effect, resulting in a larger spectral shift caused by the same amount of hydrogen.

The invention discloses a femtosecond laser directional induction etching system and method based on nanopore anchoring. The system comprises a femtosecond laser, a beam expander L1, a half-wave plate L2, a polarization beam splitter L3, a first reflector L4, a second reflector L5, a long-wave-pass dichroscope L6, a non-polarization beam splitter L7, an infinity correction objective lens L8, a semi-reflecting and semi-transmitting mirror L9, a convex lens L10, a third reflector L11, a sleeve lens L12, a power meter and a CCD camera. And in the multi-pulse irradiation process, by means of the local field enhancement effect, a subsequent structure is induced to be etched in the direction perpendicular to laser polarization with the nanopore as the starting point, and controllable machining of the nanostructure with the line width as low as 15 nm on the surface of the dielectric material is achieved. According to the invention, the growth path of the groove structure is determined by the anchoring position of the nanopore and the polarization direction of the laser, so that the method has good processing control capability and system stability.

A metal-medium composite sub-wavelength array and gain medium assisted electric field enhanced substrate design is established based on CST software, a periodic array transmission enhanced structure is solved by adopting an FEM finite element method and an FDTD time domain finite difference method, two circular ring structures are combined, the circular ring structures are changed into double C-shaped structures which are symmetrically placed, and the array transmission enhanced structure is formed. The conduction electrons are gathered to the middle position of the c-shaped ring hole; and the electric field is further effectively enhanced. The method provides theoretical guidance and experimental basis for amplification of electromagnetic signals and further enhancement of a local field, and has important academic value and practical significance.

The photovoltaic cell comprises a silicon substrate, a doping layer is arranged on the surface of the silicon substrate, a PN junction is formed on the silicon substrate, and when sunlight irradiates the silicon substrate, electric energy can be generated. The doping layer is provided with a grid line, and the grid line is electrically connected with the doping layer, and can collect and export electric energy generated in the doping layer. The grid line is formed by sintering conductive paste, after the conductive paste is sintered into the grid line, first laser is radiated to the grid line, the radiation depth of the first laser on the photovoltaic cell is not larger than 2 microns, at the moment, glass oxide in the grid line is of a compact net-shaped structure, the local field enhancement effect of metal particles is restrained, and no characteristic peak exists in a Raman spectrum shown by the grid line. The quality state of the grid line is indicated through the state of the spectral analysis grid line formed by Raman detection, and the method can reduce the possibility of damage to the grid line in the detection process.

The invention discloses an enhanced Smith-Perot terahertz radiation device and method based on a metasurface, and belongs to terahertz radiation. According to the enhanced Smith-Perot terahertz radiation device based on the metasurface provided by the invention, the penetrating composite hole digging unit is arranged on the metasurface structure, the cross section of the hole digging unit is of the cross structure formed by vertically intersecting the first rectangle and the second rectangle, and the center of the cross structure is the center of a circle, so that the specific hole digging structure can improve the radiation efficiency of the terahertz radiation device. Through cooperation with periodic arrangement of the whole metasurface in a two-dimensional array mode, the local field enhancement characteristic of the metasurface can be more effectively utilized, specifically, vertically-intersected rectangles form a hollow channel, charges are gathered due to the fact that no medium exists at the edge, and a high-strength electromagnetic field is formed in a cross area in combination with an evanescent field generated by electron beam glancing. The center of a circle coincides with the center of the cross structure, the electric field distribution symmetry is optimized, the scattering loss is reduced, the energy is further focused, and the radiation intensity is improved.

The invention discloses a high-sensitivity reconfigurable sensor and a tuning method, the sensor is of a laminated structure, the uppermost layer is a sensor body, the middle layer is a dielectric substrate, and the lowermost layer is of a microstrip line structure; the sensor body is formed by combining an artificial local surface plasmon resonance structure and a circular coupling structure, and a tiny gap is formed between the artificial local surface plasmon resonance structure and the circular coupling structure. According to the sensor, the local field enhancement characteristic of the artificial surface plasmon is utilized, a sharp Fano resonance line shape is excited through multi-mode interference, and the sensing sensitivity is greatly improved; meanwhile, the PIN diode is introduced, dynamic reconstruction of a surface plasmon mode is achieved by changing the bias voltage of the PIN diode, and the sensor has the advantages of being high in sensitivity, high in resonant frequency and adjustable in sensing frequency.

The utility model relates to a terahertz metasurface frequency multiplier based on a continuous domain bound state, which comprises a plurality of structure units arranged periodically, and the composition of each structure unit is the same. The structural unit comprises a substrate and a silicon structure located on the substrate; a hollow cylinder is arranged in the silicon structure, and after disturbance is introduced, the hollow cylinder in the silicon structure shifts in the horizontal direction, so that the symmetry of the unit structure is broken. According to the utility model, the symmetrical protection type quasi-BIC resonance is excited by introducing the disturbance on the symmetry of the unit structure, and the harmonic enhancement is realized by using the nonlinear effect caused by the local field enhancement generated by the quasi-BIC resonance. According to the utility model, the problems of low resonance quality factor and complex structure in the existing metasurface resonator and terahertz frequency multiplier are solved.

The invention belongs to the technical field of nano materials, and particularly relates to a nonmetal plasma enhanced hollow up-conversion composite structure and a preparation method and application thereof. The morphology of a rare earth doped precursor Bi2O3 is stabilized through tartaric acid, a silicon dioxide shell is controllably grown on Bi2O3 nanoparticles, and the core-shell hollow Bi2SiO5 up-conversion nanoparticles are formed through Bi2O3 and SiO2 interface diffusion and reaction driving. Through electrostatic self-assembly and nonmetal plasma W18O49 nanowire compounding, local field enhancement and photothermal effects generated by W18O49 nanowire LSPR are cooperatively utilized, and the up-conversion luminescence intensity at the 520 nm wave band is remarkably improved and reaches up to three orders of magnitude (1970 times). Based on a hollow structure and plasma photo-thermal characteristics, the BSO / W18O49 composite structure can realize efficient loading and near-infrared light-operated release of adriamycin drugs.

The present invention discloses a label-free terahertz metasurface based on the principle of bound states in a quasi-continuous domain, a preparation method, and an application. The sensor comprises: a substrate layer, and a metal resonant layer disposed on the substrate layer; the metal layer is a unit structure array formed by connecting two semicircular open resonant rings, and the unit structure array is arranged in a square period; wherein the two connected semicircular open resonant rings are formed by symmetrically deleting two identical inferior arcs in a circle with a radius of R1, and asymmetrically opening a right-side gap and a left-side gap; by setting the position of the gap of the right semicircular open resonant ring, that is, the offset α from the center of the resonator, the bound state effect in the quasi-continuous domain is achieved. By breaking the in-plane symmetry, the bound state in the continuous domain without leakage can be converted into a bound state mode in the controllable quasi-continuous domain, which can achieve local field enhancement and facilitate the strong interaction between the target cell and light.

The application discloses a method for optimizing the performance of a TMDs plasmonic phototransistor by laser impact. The method comprises the following steps: providing a composite nanostructure layer, wherein the composite nanostructure layer comprises a two-layer metal nanoparticle layer and a TMDs layer arranged between the two-layer metal nanoparticle layer; treating the composite nanostructure layer by using pulse laser impact; forming a metal electrode on the composite nanostructure layer subjected to the laser impact to obtain a phototransistor, and testing the performance of the phototransistor. In the technical scheme, the method for optimizing the performance of the TMDs plasmonic phototransistor by laser impact can make the TMDs and the metal nanoparticles undergo cooperative deformation, reduce the gap between the nanoparticles, further improve the local field enhancement effect of the "gap mode" LSPR, and cause the strain of the TMDs to increase, the band gap to decrease, the light absorption range to expand, and finally the performance of the phototransistor to be improved.

The invention provides a crop disease detection method and device based on a terahertz metamaterial sensing array, and the method comprises the following detection steps: S1, a detachable enrichment unit is adopted to adsorb target objects on the leaf surface of a to-be-detected crop living body, and the target objects comprise pathogenic microorganism spores and volatile organic compounds; the enrichment time is 2-3 minutes under the condition of 15-30 DEG C; under the condition that the temperature is lower than 15 DEG C, the enrichment time is 3-5 minutes. According to the invention, a functionalized biological probe modified heterogeneous terahertz metamaterial sensing array is combined with an AI model, precise capture of disease early-stage trace markers is realized by virtue of a metamaterial local field enhancement effect, and environmental interference is effectively counteracted by virtue of a reference unit; the device is integrated with handheld design, field in-situ detection can be achieved without damaging crops, operation is simple, and the problems that early detection is difficult, interference is large and practicability is poor in a traditional method are directly solved.

The invention relates to a low-threshold plasmon graphene all-optical nonlinear activator which comprises a substrate, the substrate is covered with a gold film, a device pattern is etched on the gold film, and the gold film is covered with a graphene film. The gold film pattern of the plasmon structure can generate an extremely strong local field enhancement effect, and the interaction between light and graphene is remarkably enhanced; the light-substance interaction is enhanced by utilizing the graphene Follicle blocking effect and the ultrafast carrier dynamics and combining the local field enhancement effect of the plasmon structure, so that the low-threshold nonlinear activation is realized. The activation threshold value of the device is as low as 7.03 nW, the accuracy rate of the device in MNIST handwritten number recognition reaches 96.7%, a low-power-consumption and high-energy-efficiency optical domain processing scheme is provided by eliminating a photoelectric conversion link, and the calculation practicability of an optical neural network is remarkably improved.

The invention belongs to the technical field of blood sodium in-vivo detection, and particularly relates to a non-invasive in-vivo blood sodium concentration detection system and a non-invasive in-vivo blood sodium concentration detection method which are combined with a terahertz spectrum technology and photoacoustic microscopic imaging. According to the invention, through short-wave photoacoustic microscopic imaging, high-spatial-resolution positioning of subcutaneous microvessels is realized, and accurate coordinates are provided for targeted detection; meanwhile, through a double-pulse differential photoacoustic detection technology, terahertz photoacoustic response from blood sodium ions is specifically extracted from complex tissue signals, and the strong water background is effectively inhibited; by introducing the terahertz local field enhancement module, the energy loss is compensated while the hyperspectral specificity is ensured by adopting narrow-band filtering, and the detection sensitivity is remarkably improved.

The application relates to a low-threshold plasmonic graphene all-optical nonlinear activator, which comprises a substrate, a gold film is covered on the substrate, a device pattern is etched on the gold film, and a graphene film is covered on the gold film. The gold film pattern of the plasmonic structure can generate a very strong local field enhancement effect, significantly enhancing the interaction between light and graphene; by utilizing the Pauli blocking effect and the ultrafast carrier dynamics of graphene, combining the local field enhancement effect of the plasmonic structure to strengthen the light-matter interaction, low-threshold nonlinear activation is realized. The device activation threshold is as low as 7.03 nW, and the accuracy in MNIST handwritten digit recognition is 96.7%; by eliminating the photoelectric conversion link, a low-power-consumption, high-energy-efficiency optical domain processing scheme is provided, and the practicability of optical neural network calculation is significantly improved.

The invention provides a method for forming elastic strain through laser shock to enhance the electrical property of a two-dimensional material, and belongs to the technical field of laser nanoscale processing of semiconductor transistors. The method comprises the following steps: firstly, transferring metal nanoparticles prepared in advance to a substrate containing a two-dimensional material, and further preparing a polymer film layer on the metal nanoparticles; stripping the obtained sample from the substrate, turning over the sample, and transferring the sample to a target substrate; and finally, pulse laser shock is used for treatment, so that the metal nanoparticles protrude relative to the upper surface of the polymer film, and the two-dimensional material obtains stable elastic strain. According to the method, the two-dimensional material can obtain stable elastic strain in the photoelectric transistor including but not limited to flexibility, the local field of the LSPR of the metal nanoparticles enhances the two-dimensional material cooperating with the elastic strain, so that the light absorption range of the prepared photoelectric transistor is enlarged, and the electrical property is remarkably improved; therefore, the flexible electronic device with high photoresponsiveness and outstanding electrical properties is manufactured.

The invention discloses a hydrogen sensing probe and a preparation method thereof.A nanowire array provides a high specific surface area and a three-dimensional channel structure, the contact efficiency of a sensitive layer and hydrogen is improved, a path is provided for light / gas transmission, sensitivity and response / recovery kinetics are considered, meanwhile, a traditional additional endoscope structure is abandoned, and the hydrogen sensing probe has the advantages that the structure is simple, the cost is low, and the application range is wide. A Fabry-Perot interference cavity formed by the second reflecting layer and the first reflecting layer enhances the back-and-forth interaction between light and the sensitive layer, improves the spectrum drift amplitude and the signal-to-noise ratio and reduces the influence of environmental factors, and the nanowire array is coupled with an end face emergent light field and / or a reflecting light field to form a local field enhancement effect, so that the detection sensitivity is improved. And superposition with a Fabry-Perot interference effect is carried out, so that the change caused by the same hydrogen generates larger spectrum shift.

The application belongs to the technical field of terahertz detection, and discloses a terahertz metamaterial enhanced spectral detection system, which comprises the following steps: constructing a metamaterial enhancement factor tensor matrix according to the interaction between a terahertz wave and a metamaterial; based on the metamaterial enhancement factor tensor matrix, optimizing local field enhancement and surface plasmon resonance of a target sample to obtain a characteristic enhancement spectroscopy mapping function; based on the characteristic enhancement spectroscopy mapping function, constructing a multi-dimensional detection characteristic space; based on the multi-dimensional detection characteristic space, forming a spectral signal enhancement topology network; based on the spectral signal enhancement topology network, generating an enhanced spectral feature discriminant function; and based on the enhanced spectral feature discriminant function, obtaining a high-precision terahertz spectral detection result; the application can mine the internal correlation between spectral features, enhance the comprehensive characterization of sample information, and thus realize high-precision terahertz spectral detection.