178 results about "Thz waves" patented technology

A detecting apparatus for detecting information of a liquid object or sample includes a transmission path, a THz wave supplying unit, a THz wave detecting unit, and an infiltrative holding member for infiltration and holding of a liquid object. The supplying unit supplies an electromagnetic wave in a frequency range between 30 GHz and 30 THz to the transmission path. The detecting unit detects the THz wave transmitted through the transmission path. The infiltrative holding member is set at a location containing at least a portion in which an electric field distribution of the THz wave propagating along the transmission path extends.

Electromagnetic radiation sources operating in the Terahertz (THz) region capable of overcoming the Manley-Rowe limits of known optical schemes by achieving phase matching between a THz wave and optical pulse in a nonlinear waveguide, or by achieving both phase and group velocity matching between a THz wave and optical pulse in a nonlinear waveguide to yield even higher efficiencies in converting optical power to the THz region.

In a micro-bridge structure in which a temperature detecting portion (diaphragm) including a bolometer thin film is supported by a supporting portion in a state floated from a circuit substrate, a reflective film reflecting a THz wave is formed on the circuit substrate, an absorbing film absorbing the THz wave is formed on the temperature detecting portion, and an optical resonance structure is formed by the reflective film and temperature detecting portion. A gap between the reflective film and temperature detecting portion measures approximately ¼ infrared wavelength (e.g., 1.5 to 2.5 μm). Sheet resistance of the temperature detecting portion is set in a range in which an absorptance of the THz wave becomes a predetermined value or above on the basis of the THz wave (approximately 10-100 Ω / sq.). The absorptance of the THz wave is drastically improved while using the structure and manufacturing technique of a bolometer-type infrared detector.

The invention relates to the field of metamaterial devices and provides a switching-controllable THz wave metamaterial perfect absorber (MPA) and a control method thereof. The switching-controllable THz wave metamaterial perfect absorber comprises a substrate, an MIT (metal-insulator transition) layer positioned on the substrate, a dielectric layer positioned on the MIT phase change layer and metal opening resonance units positioned on the dielectric layer and being in cyclic arrangement, and the on / off of the absorber at the resonance frequencies of the metal opening resonance units is realized through changing the conductivity of the MIT phase change layer. According to the invention, the variation of the conductivities of the MIT phase-change material before and after phase change is utilized to change the absorptivity of the absorber, so that the THz MPA can be turned on / off near the resonance frequency of the metal opening resonance units, initiative control of the electromagnetic transfer characteristics of THz wave bands at the specific frequency, and accordingly, a larger on-off ratio or modulation depth can be obtained; and the switching-controllable MPA adopting the substrate-vanadium dioxide-dielectric layer-SRRs (Split Ring Resonators) four-layer structure can control the conductivity of vanadium dioxide through an external field so as to control the absorptivity of the MPA.

The invention relates to the non linear optical frequency conversion. To realize output of high power THz wave which can be continuously tuned, and stable running at room temperature, the technical scheme used by the invention is that: a tunable terahertz radiation source based on difference frequency cherenkov effect is composed of a laser device, a frequency doubling crystal, a double wavelength parametric oscillator, a harmonic mirror, a polarization filter, a combined beam mirror, a column lens and a difference frequency crystal; the harmonic mirror is placed between the frequency doubling crystal and the double wavelength parametric oscillator; the double wavelength parametric oscillator is II type phase matching KTP (Potassium Titanyl Phosphate) crystal OPO (Optical Parametric Oscillator); the polarization filter, the combined beam mirror and the column lens are arranged between the parametric oscillator and the difference frequency crystal; the difference frequency crystal is amagnesium oxide doped lithium niobate crystal with molecular formula of MgO:LiNbO3 or MgO:LN, and the generated THz wave is coupled and output by an Si prism on the side surface of the difference frequency crystal. The tunable terahertz radiation source based on difference frequency cherenkov effect is mainly applied to the optical frequency conversion.

The invention discloses a THz (Terahertz) wave modulator. The THz wave modulator comprises a semiconductor substrate (1), MOSFET (Metal-Oxide-Semiconductor Field Effect Transistor) arrays (2), metamaterial resonance unit arrays (3), a first metal plate (4) and a second metal plate (5), wherein THz wave can permeate the semiconductor substrate (1), the MOSFET arrays (2) are distributed on the semiconductor substrate (1) according to a certain period, the metamaterial resonance unit arrays (3) are prepared on the MOSFET arrays (2), the first metal plate (4) is connected with a source electrode and a drain electrode of each MOSFET, and the second metal plate (5) is connected with a grid electrode of each MOSFET. According to the THz wave modulator disclosed by the invention, the working voltage of the MOSFET is very low, and thus the THz wave modulator prepared by the MOSFET can work under low voltage; and the switching time of the MOSFET is extremely short, the magnitude order of the switching time is 10-100ns, and thus the modulating rate of the THz wave modulator prepared by the MOSFET is larger than 10MHz.

The invention relates to a fast scanning method based on the passive imaging of a single wave beam THz wave. Aiming at the problems of longer scanning time and overhigh system construction cost in an earlier scanning imaging method of the single beam THz wave, a rocker of a crank and rocker mechanism is adopted to drive a line scanning plane mirror to sway horizontally so as to achieve fast transverse scanning motion, and a field scanning plane mirror swaying vertically in a reciprocating way is utilized to realize longitudinal scanning motion, thereby realizing the two-dimensional scanning imaging over object space. On the premise of construction cost reduction, the invention greatly improves the scanning speed per se and simultaneously amplifies the scanning viewing field. In addition, the invention is not only suitable for the passive type THz wave single wave beam scanning imaging, but also suitable for the active type single wave beam scanning imaging of the THz wave.

A Pound-Drever-Hall frequency stabilizing system of a dual-cavity dual-frequency solid laser device comprises the dual-cavity dual-frequency solid laser device, two independent heterodyne interferometer systems, two frequency regulators and an F-P (Fabry-Perot) optical resonant cavity. The optical resonant cavity is used as frequency stabilizing reference, the two independent heterodyne interferometer systems are used for detection to obtain two channels of error signals, the two frequency regulators are driven, and two working frequencies of the dual-cavity dual-frequency solid laser device are simultaneously locked at two resonance frequencies of the F-P optical resonant cavity. The F-P optical resonant cavity is used as the frequency stabilizing reference, the two working frequencies of the dual-cavity dual-frequency solid laser device are stabilized simultaneously, the laser frequency stability is higher than 10<-10>, and the Pound-Drever-Hall frequency stabilizing system can be widely applied to fields of interferometry for absolute distances of synthesis waves, generation of THz waves and the like.

A THz radiation source comprising a dual waveguide heterostructure is provided. The dual waveguide heterostructure includes an optical waveguide contained within a larger THz waveguide layered structure. The radiation source provides a coherent guided wave of THz radiation which is generated via difference frequency mixing in a gain medium with a large second-order nonlinearity and propagated with low THz loss by a dielectric medium in the layered waveguide structure. The THz radiation source is compact, has a high power output, and may be operated in continuous-wave (CW) mode at room temperature.

The invention belongs to the technical field of terahertz wave detection, specifically discloses a terahertz wave detector, a detection system and a detection method. The terahertz wave detector comprises a lens for receiving a first optical signal and outputting a second optical signal after filtering and focusing, a detecting element for converting the second optical signal output by the lens to an electric signal to output, a signal amplifying circuit for filtering and amplifying the electric signal output by the detecting element to output, and a power supply for supplying work voltage to the detecting element and the signal amplifying circuit. The invention can detect terahertz wave to be beneficial to all terahertz wave scientific and technical research and development.

There are disclosed a nonlinear optical crystal 1 which can generate a THz wave by a parametric effect; a pump light incidence apparatus 12 for allowing a pump light 2 to be incident upon the nonlinear optical crystal; and a seed light injection apparatus 14 for injecting a seed light 5 having a variable frequency in a generation direction of an idler light 3 generated by the pump light. The seed light injection apparatus 14 comprises angle dispersion compensation means 16 set so that an incidence angle θIN of the seed light upon the nonlinear optical crystal 1 substantially equals to a desired phase matching condition regardless of a wavelength.

The invention relates to a laser and provides a dual-wavelength tunable inner cavity tera-hertz parametric oscillator and a using method thereof to realize the output of continuous tunable dual-wavelength high-power THz wave and the stable operation at room temperature. The invention adopts a technical proposal that: a pumplight resonant cavity consists of a planar holophote, a laser and an output mirror; the laser is a quasi-continuous semiconductor laser array side-pumped neodymium yttrium aluminum garnet Nd:YAG5 laser; a back pressure type electro-optical switch Q consisting of monopotassium phosphate KD P crystal and a polaroid is arranged between the planar holophote,and the laser; a TPO resonant cavity consisting of a magnesium-doped lithium niobate MgO:LiNbO3 crystal and two cavascopes is arranged between the laser and the output mirror; and the optical axis of the TPO resonant cavity and the optical axis of the pumplight resonant cavity are non-colinear; and the side of the magnesium-doped lithium niobate MgO:LiNbO3 crystal and an array silicon prism are coupled to output the tera-hertz wave. The dual-wavelength tunable inner cavity tera-hertz parametric oscillator and the using method are mainly used for manufacturing the laser.

The invention discloses a method for accurately determining optical parameters of edible oil by utilizing a terahertz time-domain spectroscopy. By utilizing a transmission terahertz time-domain spectroscopy (THz-TDS) device, a THz time-domain spectroscopy of a sample cell without a sample is measured as a reference signal, and then a THz time-domain spectroscopy of the sample cell with the sample is measured as a sample signal; and a measurement value of a transmission coefficient of the sample in a terahertz waveband can be obtained by evaluating the ratio of Fourier transforms of the sample signal to the reference signal, then a three-layer transmission function model containing a container is utilized, and a Nelder-Mead search method and a trust region smoothing method are used to fit the measurement value of the transmission coefficient of the sample in the terahertz waveband, thereby accurately determining the refractive index and the absorption coefficient of the edible oil in a corresponding terahertz waveband. The method fully considers multiple reflection effect during the propagation of THz wave in a plurality of layers of media, considers the influence of noise and measurement error, effectively improves the measurement accuracy of the optical parameters of the edible oil, and helps to apply a THz-TDS technology to quantitative detection occasions such as component analysis of the edible oil and so on.

The invention discloses a free electron laser based tunable narrow-band compact terahertz radiation source. The free electron laser based tunable narrow-band compact terahertz radiation source comprises a laser source, a pulse accumulation light path, a reflecting mirror, a photocathode multi-cavity microwave electron gun, a solenoid coil and an undulator, wherein laser pulses emitted from the laser source are accumulated by n times through the pulse accumulation light path to generate a laser pulse string composed of 2n laser pulses, the laser pulse string irradiates on the surface of a negative electrode of the photocathode multi-cavity microwave electron gun by the reflecting mirror, and an electron bunch string is emitted from the surface of the negative electrode by a photoelectric effect, is accelerated by a microwave field generated by a microwave power source in a chamber of the photocathode multi-cavity microwave electron gun and enters the undulator after being transversely focused by a magnetic field of the solenoid coil so that electromagnetic radiation associated with THz waveband is stimulated. The technical scheme disclosed by the invention has the characteristics of compact structure, continuous and adjustable frequency and narrow bandwidth, and is easy to implement technically.

The invention relates to a manufacturing method for a broadband THz wave absorber unrelated to wide-angle polarization. The manufacturing method includes that semiconductor silicon with certain doping concentration is selected, a photolithography technique and an ICP (inductively coupled plasma) technique etching or a chemical corrosion technique are adopted on the surface of a silicon wafer to obtain periodically arranged grating layers with reduced reflectivity, and the rest part of the grating layers is a substrate layer with reduced transmissivity. By the arrangement, broadband absorber unrelated to the wide-angle polarization is realized in a THz band. Compared with a conventional metamaterial absorber, the high-doping silicon substrate absorber with the two-dimensional grating structure has the advantages of high absorption frequency band, unrelated to polarization, wide in incident angle and the like; the manufacturing method of the absorber is wide in material taking, simple and efficient, convenient to manufacture and wide in application range; the broadband THz absorber unrelated to the polarization can be manufactured according to actual application scenarios and demands, and absorption rate, absorption frequency band and absorption broadband can be regulated through regulation of structural parameters.

The invention relates to nonlinear optical frequency conversion, and belongs to the interdisciplinary field of the terahertz radiation source technology and the optical frequency comb technology. For providing a terahertz frequency comb device based on optical rectification in a periodically poled crystal and a modulation method, and achieving an effect that the wide spectrum output is implemented in a range of 0.2-3.5 THz, a free spectrum range can reach 0.5 THz, and the device can run stably at room temperature, the invention adopts a technical scheme as follows: the terahertz frequency comb device based on the optical rectification in a periodically poled crystal is composed of a laser device, a periodically poled crystal and a receiving / detecting system, and a beam splitter and a glass convex lens are configured between the laser device and the periodically poled crystal; a polyethylene lens is arranged between the periodically poled crystal and a detector; generated THz waves areoutputted perpendicular to the side face of the crystal, and collected by the polyethylene lens; and the receiving / detecting system comprises a photoconductive antenna detector, a computer controllerand a delay line. The device and method provided by invention are mainly applied to nonlinear optical frequency conversion.

The invention relates to a device for generating terahertz waves, in particular to a device for generating tunable narrowband terahertz waves by using optical difference frequency. The device comprises a pumping light source, an idler frequency light source, a nonlinear crystal and a controller. The nonlinear crystal is arranged on the light path of the co-linear beam emitted by the pumping light source and the idler frequency light source. The controller is connected with the idler frequency light source and the nonlinear crystal respectively. In order to solve the technical problem of generating THz radiation by using optical means in the background technology, the invention provides the device for generating tunable narrowband terahertz waves by using optical difference frequency. The device with simple and compact structure is operated and debugged easily. The narrowband THz waves are output quickly and continuously, and are tunable; and the output stability of the THz waves is high.

The present invention relates to one new kind of thermal wave detecting system. It adopts THz wave as heat source for heating object; thermal imaging instrument to monitor the varying temperature field in the surface of the sample and detect the phase relation between the variance in the temperature field and the heat source applies the THz wave; synchronous or time sequence controller to control the emission of the THz wave and the detection of thermal imaging instrument; and computer for thermal wave transmission calculating processing and data fitting, so as to obtain the inner fault and heterogeneity information from the temperature field variation.

The invention relates to a method for continuously regulating central frequency and spectrum width of THz (terahertz) wave. A bundle of ultrafast laser pulse passes through a movable birefringence crystal oblique split pair and a zero-order quarter wave plate to generate a novel specially-polarized light field by a polarizing gate method. The novel light field passes through a polarizer to obtain laser pulse with width of narrow pulse with linear polarization. Laser pulses different in width are obtained by controlling inserting quantity of the birefringence crystal oblique split pair, and accordingly the function of regulating central frequency and spectrum width of the THz wave is achieved. A device is simple and easy to operate, the width of the novel laser pulse can be changed only two crystals of the birefringence crystal oblique split pair simultaneously move oppositely at equal distance, and accordingly the central frequency and the spectrum width are adjusted. The method is suitable for light sources of various pulse widths and wavelengths.

Provided are an apparatus for generating / detecting terahertz wave and a method of manufacturing the same. The apparatus includes a substrate, a photo conductive layer, a first electrode and a second electrode, and a lens. The photo conductive layer is formed on an entire surface of the substrate. The first electrode and a second electrode are formed on the photo conductive layer. The first and second electrodes are spaced from each other by a certain gap. The lens is formed on the first and second electrodes. The lens is filled in the gap between the first and second electrodes.

This invention relates to one special fiber and to one with low consumption of Hertz wave, which is characterized by the following: realizing THz wave transmission within range of 30 mum-3mm; using current two steps or one step to produce and the fiber materials can adopt plastic materials as base materials to absorb consumption, such as high intensity HDPE, low intensity LDPE, Teflon or TPX or polypropylene non polarization polymer.

The invention discloses a broad-tuning waveguide terahertz radiation source. The broad-tuning waveguide terahertz radiation source comprises a laser pump source, a dual-wavelength parametric oscillator, a cylindrical lens and a panel waveguide, wherein the laser pump source outputs 532nm Q-switched pulses to the dual-wavelength parametric oscillator, the dual-wavelength parametric oscillator generates dual-wavelength pulses which are within the range, wherein the center of the range is a degeneracy point, and the radius of the range is 1064nm, the dual-wavelength pulses are focused through the cylindrical lens, and are coupled to a core layer of the panel waveguide, narrow-linewidth THz waves are generated through the second-order non-linear difference frequency effect, a THz radiation mode is generated through the Cherenkov phase matching mode, and sidewise coupling output is achieved. Due to the fact that the structure is adopted, the tuning range is expanded, broadband tuning within the range from 0.1THz to 7THz can be achieved, high-efficiency coupling of the THz waves is achieved, coherent THz radiation output with broad tuning and the narrow linewidth is finally achieved, and the broad-tuning waveguide terahertz radiation source can be widely applied to the fields such as the biomedicine imaging field, the high-resolution spectral analysis field, the material detection field and the medical diagnosis field.

The invention provides a microprobe scattering type terahertz waveband dielectric constant detecting device. The microprobe scattering type terahertz waveband dielectric constant detecting device consists of a first infrared laser (1), a second infrared laser (2), a front-end polarization maintaining fiber (3), a coupling beam splitter (4), a rear-end polarization maintaining fiber (5), a THz wave transmitting antenna (6), a THz wave beam splitting plate (7), a THz wave reflector (8), a first motivation ceramic (9), a micro-nano probe (11), a second motivation ceramic (17), a paraboloidal mirror (10), a THz wave power detector (14), a function generator (16) and a lock-in amplifier (20). Signals which are related to samples can be acquired accurately, and the dielectric constant of the samples is calculated by a calculating method based on a detection result. The microprobe scattering type terahertz waveband dielectric constant detecting device has the characteristics of high resolution ratio, high flexibility and high operationality, has ability of testing on a plurality of frequency bands and frequency points, and brings convenience for multi-disciplinary research on mesoscale.

The invention relates to a THz modulator based on graphene-metal composite microstructure and preparation thereof. The THz modulator includes: a polymer flexible substrate layer; a doped semi-conductor epitaxial layer; a A1203 insulating-active region structure composite layer which grows on the doped semiconductor epitaxial layer and is composed by superposing at least one A1203 insulating-active region sub-structure which includes an A1203 insulating layer which is disposed therebelow and a graphene microstructure layer and a metal microstructure layer which grow on the A1203 insulating layer, the metal microstructure layer being disposed inside the graphene microstructure layer and is arranged spaced from the graphene microstructure layer to form the active sub-region structure of the THz; a metal layer which is vapor plated on one active sub-structure in the uppermost and processed to form a metal top electrode. Compared with prior art, according to the invention, the THz modulator can effectively regulate THz waves, has high quality factor, excellent adjustability and great modulation depth, etc.

[Task] To provide the THz wave generator restricting increase in manufacturing cost or large size of the entirety of the apparatus and generating efficiently the several-W THz wave.[Means for Resolution] In a THz wave generator for generating a THz wave from a THz wave generating element by inputting a plurality of laser beams having different wavelengths to the THz wave generating element, at least one laser beam among the plurality of laser beams is formed into a pulse beam by the pulse generator and the pulse beam is amplified by an optical amplifier E and then the pulse beam is inputted to the THz wave generating element F. Preferably, the plurality of laser beams having different wavelengths are generated by inputting single wavelength beam to a multi wavelength generator from single mode laser light source and by inputting light waves having a plurality of wavelengths generated from the multi wavelength generator to wavelength selecting means.

Provided are a THz-wave generation / detection module and a device including the same, which increase heating efficiency and are miniaturized. The module includes a photomixer chip, a lens, a PCB, and a package. The photomixer chip includes an active layer, an antenna, and a plurality of electrode pads. The lens is disposed on the photomixer chip. The PCB includes a plurality of solder balls connected to the electrode pads, under the photomixer chip. The package surrounds a bottom and side of the PCB, and dissipates heating of the active layer, which is transferred from the electrode pad of the photomixer chip to the PCB, to outside.

The structure of THz signal high sensitivity detector and detecting head is as follows. It makes association of photon crystal THz micro cavity and semi conductor transistor on the base of the semiconductor. It generates big density of field energy of the micro cavity when the THz wave injects, the generated thermal effect will make electric hollow cavity pair, amplifies the carrier after flowing into the base of the transistor, generating current of the outside circuit, to detect THz signal to realize high sensitivity THz signal detection. It accumulates several detectors to form a THz harmonic matrix, with each harmonic cavity receiving specific location, and intensity of THz light. Being amplified and stored, the signal can get a complete THz image to realize timely photo taking function. It uses special signal amplification circuit to realize elimination of background THz radiation noise.

The invention relates to a semi-conductor laser device capable of outputting double-wavelength laser for optical mixing to generate THz waves and a manufacturing method. The semi-conductor laser device comprises a semi-conductor laser device epitaxy structure formed by a substrate, a lower limiting layer I, a lower waveguide layer I, an active layer I, an upper waveguide layer I, an upper limiting layer I, a regenerating mechanism, a lower limiting layer II, a lower waveguide layer II, an active layer II, an upper waveguide layer II, current blocking layers, an upper limiting layer II and a P-type Ohm contact layer. The two current blocking layers are formed on the two sides of the longitudinal shaft of the semi-conductor laser device respectively in a wet oxidation method or a proton bombard method, and the current spreading effect of the active area II is effectively prohibited. The THz waves generated by optical mixing achieved through the double-length laser are easy to produce and achieve, light output through optical cavity coupling is coaxial, and synchronous control is achieved. The coaxial double-wavelength semi-conductor laser device enables a THz source to be simple in structure, cost is reduced, continuous output power is large, and the THz source can work at the room temperature.