443 results about "Terahertz detector" patented technology

The invention provides a detector comprising a metamaterial absorber and a micro-bolometer arranged to detect terahertz (THz) radiation. The metamaterial absorber can absorb multiple frequency bands, from the infrared and the THz regions of the electromagnetic spectrum. The detector is scalable to be suitable for use in a focal plane array.The invention also provides a hybrid of a plasmonic filter, e.g. for optical radiation, and a metamaterial absorber for terahertz (and / or infrared) radiation, to create a single material capable of absorbing narrow band terahertz radiation and filtering radiation in another part of the spectrum, e.g. optical radiation. Such material has great potential in future imaging technology where hybridisation can maximise the spectral information density of an optical system.

A microbolometer includes a micro-bridge structure for uncooling infrared or terahertz detectors. The thermistor and light absorbing materials of the micro-bridge structure are the vanadium oxide-carbon nanotube composite film formed by one-dimensional carbon nanotubes and two-dimensional vanadium oxide film. The micro-bridge is a three-layer sandwich structure consisting of a layer of amorphous silicon nitride base film as the supporting and insulating layer of the micro-bridge, a layer or multi-layer of vanadium oxide-carbon nanotube composite film in the middle of the micro-bridge as the heat sensitive and light absorbing layer of the microbolometer, and a layer of amorphous silicon nitride top film as the stress control layer and passivation of the heat sensitive film. The microbolometer and method for manufacturing the same can overcome the shortcomings of the prior art, improve the performance of the device, reduce the cost of raw materials and is suitable for large-scale industrial production.

The invention relates to non-linear optical frequency conversion and the application of the non-linear optical frequency conversion and provides a method and a device which can widen the preparation requirements for a biological sample, do not need preparation of the sample, are high in measurement sensitivity, and can achieve high resolution, fast and real-time biological sample moisture content and distribution imaging measurement. The technical scheme is that the biological tissue moisture measurement device based on terahertz wave attenuated total reflectance (ATR) is composed of a tunable terahertz (THz) radiation source, a non-spherical face lens assembly, a total reflection prism, a two-dimensional mobile scanning platform, a terahertz wave detector and a computer. The total reflection prism is placed in the middle of the non-spherical face lens assembly, the face to be tested of a biological sample to be tested clings to the top face of the total reflection prism fixed on the two-dimensional mobile scanning platform, terahertz (THz) waves are projected to the terahertz detector through the non-spherical face lens assembly, and a detection result of the terahertz detector is output to the computer. The biological tissue moisture measurement device and the method based on the terahertz wave attenuated total reflectance (ATR) are mainly used for biological sample moisture content and distribution imaging measurement.

A diagnostic apparatus including a terahertz generator taking the form of a femtosecond laser exciting either an optoelectric crystal of a photoconductive dipole antenna the terahertz radiation is directed onto a target preferably held close by or abutting an enclosure including a reflection receiving window and housing terahertz detector for detecting terahertz radiation. Preferably the terahertz radiation generator forms part of the receiving window. The enclosure has a modified atmosphere to permit ready transmission of terahertz radiation. A beam splitter is positioned between the laser and the terahertz generator to split off a probe laser beam from the terahertz inducing laser radiation which is also directed to the detector means. The output from the detector being determined by the amplitude of that part of the reflected teraherz radiation wave coaligned with the probe laser at the detector. A delay is positioned in the probe laser path to altering the length of the probe laser path over terahertz subwavelength distances so that different parts of the terahertz wave form can be interrogated by the probe laser to thereby ascertain the shape and dimensions of the reflected terahertz radiation.

The invention discloses a film system structure for enhancing Terahertz radiation absorption rate and a preparation method of the film system structure, wherein the film system structure is located at the top layer of a sensitive unit of a Terahertz detector and comprises a dielectric thin film and a Terahertz absorption layer located on the dielectric thin film; the dielectric thin film is a low-stress silicon nitride or silicon oxide thin film prepared by PECVD (Plasma Enhanced Chemical Vapor Deposition) frequency-mixing technology and etched into a micro nanometer-level rough surface by reactive ions; and the Terahertz absorption layer is prepared on the rough-surface dielectric thin film via a magnetic control sputtering method. As surface-to-volume ratio of the Terahertz absorption layer is increased by the rough surface structure of the dielectric thin film, the Terahertz radiation absorption rate is effectively enhanced; and the preparation process is simple and reasonable, and large-area preparation and integration are easy to carry out, so that the film system structure can be widely applied to the field of various Terahertz detecting and imaging technologies and strong support is provided to the development of high-performance Terahertz detectors.

A system and method for THz imaging utilizing a single THz detector that detects an image of a large area and provides good spatial details (high resolution). In one aspect, the THz beam passes through an object to be imaged, and a THz fiber bundle having a plurality of THz fibers collect the THz beam on the other side of the object and transmit the beams to a single THz detector. Each THz fiber imparts a different time delay to the beam traveling therein. Therefore, the spatial information is converted into time information in the form of time delays. Knowing the distance each part of the imaging area must travel (hence the time it takes) before reaching the THz detector, one can recover the spatial information from the time data. In another aspect, the THz fiber bundle is replaced with a mask having an array of holes with each hole having a different depth or a different refractive index. In still another aspect, the THz fiber array is replaced with a plate holding different masks. Each mask may include holes that may be turned on / off with a distinct pattern from all of the other holes. Once the data for each mask has been received, the data for each hole may be extracted according to its modulation pattern.

The utility model relates to a device and a method for detecting the particle concentration of the gas-solid flow based on the terahertz (THz) electromagnetic emission and detection device, comprising a femto-second laser, a coupling transmission optical fiber, a photoconductive antenna type THz electromagnetic emitter, an optical delay unit, an off-axis parabolic mirror, a THz detector, a phase-lock amplifier, a high-frequency power amplifier and a data acquisition and processing system controlled by a computer. The utility model reflects the THz wave sent from the THz electromagnetic emitter in parallel via the off-axis parabolic mirror and the THz wave through the gas-solid flow is condensed to the THz detector via the off-axis parabolic mirror. The particle concentration of the gas-solid flow on the section of a pipeline can be calculated with different models according to the measured THz time domain signal. The utility model has the advantages of simple structure, convenient installation, high measuring accuracy, safe use, and wide application in fields of petroleum, chemical industry, energy, metallurgy and environment.

The invention provides a graphene field effect transistor based terahertz detector and a preparation method therefor. The detector comprises a gate electrode, a substrate layer, an insulating layer, a metal electrode layer and a graphene channel layer from the bottom up, wherein the metal electrode layer comprises a metal electrode array, and a source electrode and a drain electrode which are positioned on the two sides of a metal pattern array; the metal electrode array comprises multiple metal electrodes which are periodically arranged at intervals; the metal electrodes, the source electrode and the drain electrode are the same in thickness; the graphene channel layer is formed on the metal electrode layer; and the graphene channel layer fully covers the metal electrode array and at least partially covers the source electrode and the drain electrode. By adoption of the way, the absorptivity of the detector on terahertz radiation can be improved.

The invention discloses a room-temperature adjustable sub-Terahertz wave detector and a preparation method. A graphene field effect transistor with high migration rate and adjustable carrier concentration is taken as a basic structure unit, and the field effect transistor is provided with a group of source and drain electrodes and cleavage grid electrodes of a sub-Terahertz wave coupled antenna. The detector is integrated with log-periodic antennas and corresponding feed electrodes on a sapphire substrate; the detector is provided with a graphene conducting channel transferred in an antenna distance; an aluminum oxide gate dielectric layer is arranged on the graphene conducting channel, and finally the cleavage grid electrodes and the corresponding lead electrodes are integrated on the aluminum oxide gate dielectric layer of the graphene conducting channel, so that adjustable sub-Terahertz wave detection is realized. The detector has the advantages that the detector is an adjustable lightguide-like and photovoltaic-like detector with high speed, wide band and high response; and the integration level, technical maturity and repeatability of the device lay the foundation of large-scale application of Terahertz detectors.

The invention discloses a paper sheet quantitative detection device which is based on a terahertz time-domain spectroscopy technology and a method thereof. The detection device includes: a femtosecond laser, a beam splitter, an optical delay device, a reflective mirror, a focusing lens, a photoconductive antenna type terahertz transmitter, a polyethylene lens, a polarizer, a zinc telluride electro-optical crystal, a phase-locking amplifier, a high-power amplifier and a data collection and processing system. The invention makes use of the polyethylene lens for aligning the terahertz waves to the parallel light beams, and the polyethylene lens is used for focusing the terahertz waves on a terahertz detector after penetrating the paper sheet. The paper sheet quantitative detection method which is disclosed by the invention firstly establishes a paper sheet quantitative detection mathematical model, then respectively measures the time-domain signals of the terahertz waves penetrating the air and penetrating the paper sheet, extracts the delay time and applies the established mathematical model to calculate the paper sheet quantitative value. The invention has high precision of the measurement, strong anti-interference capability, small influence of multiple reflections and safe usage, so the invention can be used in the precise paper sheet quantitative detection of the field of paper making.

The invention discloses a two-layer micrometering bolometer and a manufacturing method thereof. The two-layer micrometering bolometer comprises a microbridge structure for a micrometering bolometer of an uncooled infrared detector or an uncooled terahertz detector, and is characterized in that: the microbridge consists of two independent bridge decks, namely an upper bridge deck and a lower bridge deck; a light absorbing material is positioned on the upper bridge deck; a thermistor material is positioned on the lower bridge deck; and four upper and lower bridge deck connecting posts on the upper bridge deck of the microbridge are connected with a metal heat transfer layer of the lower bridge deck of the microbridge. The upper bridge deck of the microbridge comprises one or more layers of light absorbing materials. The two-layer microbridge has higher light absorption rate and filling factor, and also has higher temperature uniformity and mechanical stability. The two-layer micrometering bolometer and the manufacturing method thereof can overcome the defects in the prior art, the working performance of a device is improved, and the two-layer micrometering bolometer is suitable for large-scale industrial production.

The invention relates to a terahertz detector, in particular to a grid-control graphene nano-ribbon array THz (terahertz) detector and a tuning method. The detector comprises a bottom grid 1, a low-resistivity silicon substrate 2, a double-layer graphene nano-ribbon array 3, source and drain electrodes 4 and 5, insulating layers 6, top grids 7, 8 and 9 and a driving circuit 10. The double-layer graphene nano-ribbon array 3, the source and drain electrodes 4 and 5, the insulating layers 6, the top grids 7, 8 and 9 and the driving circuit 10 are arranged on the substrate. The tuning method includes constructing grid-control double-layer graphene nano-ribbon arrays with different widths by the aid of energy gap double regulation and control mechanisms of double-layer graphene under the effects of lateral constraints and perpendicular electric fields; changing grid voltages; synchronously scanning terahertz waves in a subsection manner to achieve the purpose of detecting wide bands. The grid-control graphene nano-ribbon array THz detector and the tuning method have the advantages of high sensitivity, fast response, broad detection band widths, flexibility in regulation, simple structure, convenience in integration, small size and capability of working at room temperatures. Besides, the grid-control graphene nano-ribbon array THz detector and the tuning method can be widely applied to security inspection, drug enforcement, anti-terrorism, medical imaging, nondestructive examination, electronic countermeasure, radar, remote sensing and outer space wideband communication fields and the like.

A technique is provided for examining a subject. The technique includes illuminating at least a part of the subject with THz radiation and detecting THz radiation reflected and / or transmitted from the illuminated part and incident upon a detector array by measuring change in capacitance corresponding to the incident THz radiation.

The invention discloses an ultrathin metal membrane terahertz absorbed layer and a preparation method thereof. Absorbed layer equipment is arranged on the top layer of a terahertz detector sensing unit. An ultrathin metal membrane adjusts a craft parameter and distribution of etching agent concentration by etching and thinning metal ultrathin equipment with a big thickness in the process of etching and thinning, a microcell etching rate difference is caused, and a rough, multi-hole and melanism ultrathin metal membrane is obtained. The etching method has two types, one method enables a metal thin membrane to be etched to the ultrathin metal membrane by utilizing of a reaction ion etching method and the etching late corrosion phenomenon of a dry method, and the method has the advantages that the reaction process and the thickness of the ultrathin metal membrane are easily controlled and the like. The other method enables the metal thin membrane to be corroded to the ultrathin metal membrane by utilizing a wet process chemical corrosion method, and the other method has the advantages that the surface shape and the color of the ultrathin metal membrane are easily controlled, and the like. The surface structure of the rough, multi-hole and melanism metal thin membrane has the advantages of being high in surface body ratio and low in reflectivity, and effectively enhances absorption performance and rate of terahertz radiation.

The invention discloses a terahertz or infrared micro-bolometer, which comprises a micro-bridge structure of a micro-bolometer for an uncooled terahertz detector or an uncooled infrared detector, wherein a thermistor material and a light absorbing material in the micro-bridge structure are one of a vanadium oxide-fullerene binary composite thin film or a vanadium oxide-fullerene-carbon nanotube ternary composite thin film. The vanadium oxide composite film is formed by compounding two-dimensional vanadium oxide and zero-dimension fullerene components or two-dimensional vanadium oxide, zero-dimension fullerene and one-dimensional carbon nanotube components. The micro-bolometer and a manufacturing method thereof can overcome the defects existing in the prior art and are suitable for large-scale industrial production; and the working performance of the device is improved.

The invention discloses a terahertz time-domain spectrograph capable of entering at a fixed angle and simultaneously detecting transmission and reflection and belongs to the technical field of spectrums. The spectrograph is characterized in that a femtosecond laser device is used as an excitation source, and a beam splitter arranged at the output end of the femtosecond laser device is used for splitting one beam of laser into two beams, wherein one beam is detection light; the other beam is further split into two beams through a beam splitting prism, wherein one beam is used as pumping light and the other beam is also used as the detection light; the pumping light is gathered on a terahertz transmitter and pulse terahertz waves are generated by radiation; the generated terahertz waves are used for irradiating a sample; the terahertz waves transmitting the sample are focused on one path of terahertz detector, and the terahertz waves reflected by the sample are focused on the other path of terahertz detector; the two paths of detection light are also focused on the two terahertz detectors at the same time, and pulse terahertz wave electric field amplitude values of transmission and reflection are calibrated. In the system, a relative position between a reflecting mirror and the sample is fixed, and a transmission spectrum and a reflection spectrum of the sample can be obtained at the same time, so that the transmittance and the reflectivity of the sample are accurately obtained, the reliability of data is guaranteed and experiment efficiency is also improved.

Described are a sensor and a method for measuring a vibration of a surface obscured from view. The sensor includes a narrowband source of a terahertz beam, a beamsplitter, a beam combiner and a terahertz detector. The beamsplitter splits the terahertz beam into a sample beam for irradiating the surface and a reference beam. The beam combiner combines the sample beam scattered from the surface and the reference beam. The terahertz detector generates an electrical signal based on a modulation of the power of the combined beams due to the vibrating surface. The electrical signal indicates a characteristic of the surface vibration. Homodyne or heterodyne detection can be utilized. Advantageously, the sensor can see surfaces that are covered, concealed or otherwise obscured behind optically opaque materials, including plastic, cloth, foam, paper and other materials. Thus the sensor has a wide variety of applications where conventional vibrometers are not practical.

A terahertz detector based on an optical antenna comprises optical antennas made of polycrystalline silicon material layers and a transistor or a field-effect tube. The optical antennas are respectively arranged at the source electrode end and the drain electrode end of the transistor, the distance of the edges of the antennas and the edge of the grid electrode of the transistor is 100-500 nm, and the optical antennas and the source end, the drain end and the grid end of the transistor are isolated by filling oxides in a standard technology. The optical antennas and the grid electrode of the transistor are made of the same layer of polycrystalline silicon materials, however, doping is independently achieved through other technologies, and the thickness is 100-300 nm. The optical antennas are of a dipole antennal structure and a bow-tie antenna structure, and the doping density of the polycrystalline silicon materials is 1017-1020. According to the working scheme of the terahertz detector of the optical antenna, DC bias voltages are added on the grid electrode of the transistor, the source electrode is connected to the ground, the drain electrode floats in the air, and signal voltages are output from the drain electrode.

The invention discloses a system for improving a terahertz scanning imaging speed. The system comprises a terahertz wave source, a terahertz wave detector, a first beam splitter, a collimating lens, a second beam splitter, a planar metal reflecting mirror, a first chopper, a second chopper, a chopper controller, a first 90-degree off-axis paraboloidal metal reflecting mirror, a second 90-degree off-axis paraboloidal metal reflecting mirror, a two-dimensional electric control displacement table, an electric control displacement table controller, a computer and a data acquisition card. According to the system provided by the invention, the terahertz scanning imaging speed can be doubled at the same scanning speed by virtue of only one continuous terahertz wave source and only one point terahertz detector.

The invention, which belongs to the technical fields of security inspection equipment and image processing, discloses an active terahertz security inspection imaging method and system. The security inspection imaging system is characterized in that a data acquisition and processing system is connected with a terahertz transmitter, a terahertz linear array detector and a band-shaped beam scanning control unit respectively; a beam splitter is connected with a beam shaping optical assembly, the terahertz linear array detector and a terahertz focusing optical assembly respectively; and the band-shaped beam scanning control unit is connected with the terahertz focusing optical assembly, the band beam scanning control unit, and a tested target. In addition, according to the active terahertz security inspection imaging method, on the basis of a mode of terahertz radiation emitted by a terahertz source, one-dimensional scanning of a band-shaped beam focusing beam, and receiving by a linear array terahertz detector, irradiation and scanning of the whole target plane are completed rapidly to achieve an objective of rapid imaging and checking on a target. With the active terahertz security inspection imaging system, the imaging quality is improved. Because of the one-dimensional scanning way, the imaging time is saved; and with the array detector, the circuit system structure is simplified, the system cost is lowered, and the expenditure is reduced.

A method of determining material properties for an object under test is disclosed. The method comprises determining a thickness at a point on the object under test in a non-invasive manner. It also comprises obtaining a terahertz measurement by passing terahertz radiation through the object under test using a terahertz emitter and detecting the terahertz radiation using a terahertz detector. Finally, it comprises determining an optical property at the point on the object under test using a measurement value from the terahertz emitter and the terahertz detector and a measured value for the thickness at the point.

The invention relates to an active terahertz human body security inspection system device and an adjustment method. The active terahertz human body security inspection system device comprises a target person, a terahertz plane reflector, a terahertz focusing lens, a terahertz detector, an image analysis processing module, an air spraying device, a target automatic sensing device, a baffle, a device shell, a background plate, a terahertz source, a high-speed galvanometer and a terahertz transmission waveguide; terahertz waves radiated by the terahertz source pass through the terahertz coherence elimination-used galvanometer, and then, enter the terahertz transmission waveguide and uniformly irradiate the target person at different angles through a plurality of ports of the terahertz transmission waveguide; the surface of the body of the target person will reflect the terahertz waves which uniformly irradiate the body of the target person; the swing shaft and angle adjustment shaft of the terahertz plane reflector are controlled, so that fast scanning and imaging of the target person can be realized; and a swing angle and a rotation angle can be set according to actual experiment conditions. The device has the advantages of simplicity and easiness in operation; and the method is suitable for microwaves, terahertz waves and far infrared waves.

The invention discloses a terahertz quantum well photodetector (THzQWP)-based passive thermal imaging detection system and a method thereof. A photoconduction THzQWP is taken as a photodetector, a self-designed radiation signal denoising modulation method, a synchronous control module and a signal transmission-convergence light path are adopted, and THzQWP-based passive thermal imaging detection is finished; a thermal radiation signal is modulated by an adjustable aperture diaphragm and a wave chopper at an acquisition end of the thermal radiation signal, and the modulation frequency is set by the wave chopper; a photoconduction mode is adopted at a signal detection circuit end of the THzQWP, the THzQWP receives the radiation signal through an off-axis parabolic mirror group convergence light path and extracts a THz signal, stable bias voltage is applied, THzQWP photocurrent is converted into voltage by a transimpedance amplifier, the voltage is amplified by a low noise amplifier, anddata is read by a phase-locked amplifier; and the read signal is recorded and processed by the synchronous control module, and thermal image information is acquired finally.

The invention discloses a rapid terahertz continuous wave scanning imaging system and method and aims at providing a rapid terahertz continuous wave scanning imaging scheme. With the adoption of the scheme, the scanning imaging speed is increased, the resolution ratio is improved, and the system can stably operate at room temperature for a long time. Therefore, with the adoption of the technical scheme, according to the rapid terahertz continuous wave scanning imaging system and method, the terahertz radiation is subjected to beam splitting, and the signal to noise ratio of an imaging result is increased by introducing reference light; signal light is focused to vertically radiate to a sample, the sample is fixed on a two-dimensional translation stage, the scanning imaging is realized by changing the sample position, the two-dimensional translation stage is stable in moving speed without pause, the intensity values of the signal light and pump light are detected by using detectors of the same model, data of two terahertz detectors at corresponding positions are recorded according to the position of the translation stage, and the terahertz transmission scanning imaging result of the sample is obtained by comparison. The system and the method are mainly applied to the terahertz continuous wave scanning imaging.

The invention provides a preparation method for a polyvinylidene fluoride (PVDF) nanometer film with a beta crystal phase, which belongs to the fields of pyroelectric thin film materials and terahertz detection. The preparation method comprises the following steps: dissolving graphene oxide and polyvinylidene fluoride in an organic solvent and carrying out ultrasonic treatment and magnetic stirring so as to obtain a uniformly dispersed film-making solution; standing the film-making solution for defoaming; preparing a wet film by using a spin coating method; and subjecting the film to heat treatment in an atmospheric environment to realize drying and crystallization of the film so as to obtain the polyvinylidene fluoride nanometer film with the beta crystal phase. According to the invention, the content of the beta crystal phase in PVDF is increased by doping of GO and the PVDF nanometer film is prepared by using the spin coating method; the preparation method is simple, is easy to control, has low requirements on equipment and low cost and can realize preparation under common atmospheric conditions; and the prepared PVDF film is uniform and smooth, has good compactness and stable pyroelectric performance and provides powerful support for development of a thin-film pyroelectric terahertz detector.

The invention discloses a terahertz compressive imaging system and method. The system comprises 1, a terahertz generation and detection unit which comprises a laser source, a terahertz emitter and a terahertz detector, 2, a terahertz wave coding measurement unit which comprises a light splitter lens, a semiconductor mask plate and a digital projection device, wherein the digital projection device produces encoded pattern light beams, the light beams act on the semiconductor mask plate to cause semiconductor carrier distribution and the semiconductor mask plate allows the specific terahertz wave to go through the mask plate and keeps congruity of the specific terahertz wave and the light beam pattern so that terahertz wave spatial modulation is realized and a semiconductor mask plate coding function is realized, and 3, a terahertz reconstruction imaging unit which is used for recovering the original image through a reconstruction algorithm so that terahertz imaging is realized. Through combination of digital light processing projection and semiconductor photo-induced carrier characteristics, terahertz wave light-controlled modulation is realized. The system has the advantages of complete digitization, fast rate, high programmable capability, low cost and integration easiness.

The invention discloses a three-dimensional terahertz tomography system, a scanning method and an image reconstruction method thereof. The three-dimensional terahertz tomography system comprises a terahertz emitting source, a wave chopper, a sample rotation translation table, a light beam transmission unit, a terahertz detector and a lock-in amplifier. The imaging method comprises a scanning method for acquiring projection data and an image reconstruction method. According to the present invention, when a sample is scanned by the imaging system, only the single-frequency transmitted light intensities of each detection point are required to be recorded, such that the imaging time is reduced, and the power is high so as to image the thick object; when the image reconstruction is performed according to the projection data, the absorption rate distribution of the sample at the angle according to the projection data at each angle is obtained, and the absorption rate distribution and the terahertz light beam light intensity distribution are subjected to deconvolution, such that the actual absorption rate distribution of the sample can be obtained; and with the imaging method and the system of the present invention, the problem that the light approximation on the terahertz light beam can cause the blurred image in the existing imaging technology can be effectively solved.