80 results about "Optical rectification" patented technology

The invention discloses a shaping method of a difference frequency terahertz pulse and a shaping system thereof. In the shaping method, a laser pulse shaping device is used for realizing the programmable shaping of a laser pulse; two arrays of laser pulses passing through the converting and shaping device are regulated to be mutually vertical in polarization directions and then are overlaid in a non-linear crystal and subjected to difference frequency to generate a terahertz wave; and through controlling the wave forms and the phases of the two arrays of the laser pulses with mutually vertical polarization directions, the wave form and the electric field polarization direction of the generated terahertz pulse can be controlled and the wave form and the polarization direction of generated terahertz radiation can be detected. The invention not only can control the wave form and the pulse interval of the terahertz pulse, but also can control the electric field polarization direction of the terahertz pulse. Compared with a scheme for shaping the terahertz pulse by using a photoconductive antenna or through an optical rectification process, the invention has obvious advantages.

The invention relates to the field of rectification and purification; at present, a conventional multi-stage rectification technology is adopted in existing polycrystalline silicon production to purify trichlorosilane, rectification stages are multiple, reflux ratio is large, energy consumption is large and device investment is high; in order to overcome the problems, a technical scheme in the invention adopts a novel process of combining resin adsorption with multi-stage rectification. Coarse trichlorosilane is pre-cooled and cooled, and pumped into an adsorbing device with special divinylbenzene resin by a pump to remove boron and phosphor impurities; and then, rectification is carried out on the adsorbed trichlorosilane liquor in a three-level rectification tower to obtain the high-purity trichlorosilane. The production process disclosed by the invention not only achieves the purpose in the invention, but also has high trichlorosilane purity, lower rectification separator impurity content and can recycle the trichlorosilane for use in disproportionated reaction, so that energy consumption is further lowered, and material utilization rate is improved.

Provided are systems and methods to generate single-cycle THz pulses from a few tens of nanometers thin layer of split ring resonators (SRRs) via optical rectification of femtosecond laser pulses. The emitted THz radiation, with a spectrum ranging from about 0.1 to 4 THz, arises exclusively from pumping the magnetic-dipole resonance of SRRs around 200 THz. This resonant enhancement, together with pump polarization dependence and power scaling of the THz emission, underpins the nonlinearity from optically induced circulating currents in SRRs, with a huge effective nonlinear susceptibility of 0.8×10−16 m2 / V that far exceeds surface nonlinearities of both thin films and bulk organic / inorganic crystals and sheet nonlinearities of non-centrosymmetric materials such as ZnTe.

A system and a method for generating terahertz (THz) radiation are provided. The system includes a photonic crystal structure comprising at least one nonlinear material that enables optical rectification. The photonic crystal structure is configured to have the suitable transverse dispersion relations and enhanced density photonic states so as to allow THz radiation to be emitted efficiently when an optical or near infrared pulse travels through the nonlinear part of the photonic crystal.

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.

This invention relates to a super-quick optical technology including utilizing optical non-linear conversion technology in a laser cavity to generate THz laser, and said generator utilizes a non-linear optical rectification theory to put a THz laser generator at the beam waist in the cavity to increase its laser conversion efficiency. Since a laser oscillator is used as a pump source, the THz laser generated by non-linear optical rectification has the character of wide spectrum and high repeatability.

This invention is a method for rectifying an input digital image including warped textual information. The method includes analyzing the input digital image to determine a plurality of text line traces that track along with the warped textual lines in a substantially parallel fashion. The input digital image is subdivided into a plurality of vertical slices, each having associated first and second slice edges and an associated slice width. Vertical slice deformation models are formed for the vertical slices by identifying a plurality of text line traces that cross a particular vertical slice, and fitting a parametric function that predicts second-edge vertical coordinates for the text line traces as a function of corresponding first-edge vertical coordinates. A plurality of streamlines are formed responsive to the vertical slice deformation models. A global deformation function is formed by interpolating between the streamlines and is used to form a rectified image

The invention discloses a terahertz wave amplification device based on optical pumping substrate-free graphene. The terahertz wave amplification device comprises a THz (terahertz) radiation generation device, a THz radiation amplification device and a THz radiation detection device, wherein the three devices share a femtosecond laser through a beam splitter. Incident femtosecond optical pulses are divided into two beams through the beam splitter, wherein one beam is of an optical detection path for entering into the THz radiation detection device, the electro-optic sampling detection principle is utilized for detecting generated and amplified terahertz pulses; the other beam is further divided into two beams, namely Beam 1 and Beam 2 via the other beam splitter; the Beam 1 is of THz generated light, the optical rectification effect is utilized to generate THz radiation on the surface of a nonlinear crystal, and the radiation is irradiated onto the substrate-free graphene via an off-axis parabolic mirror as signal light; and the Beam 2 is of pumping light of the graphene, the substrate-free graphene is stimulated to realize population inversion of a current carrier, and stimulated amplification of the THz radiation is realized on the action of the THz signal light.

The invention relates to a camera shooting type multi-target locating method and device based on image rectification and belongs to multi-target locating methods and devices. The camera shooting type multi-target locating device comprises a locating platform, a control circuit board and a master controller. Cameras obtain target information on the surfaces of screens, the primary optical axis of each camera is automatically determined according to the imaging starting position of the camera, and then the imaging positions of targets in the cameras are extracted. The imaging positions are corrected through the distortion correction method based on equivalent faces. The cameras are grouped, and multi-target locating is achieved through the optical intersection measuring locating algorithm. The camera shooting type multi-target locating method and device based on image rectification has the advantages that the structure of the device is simple, reliability is high, lens distortion does not need complicated calibration and correction, extension is easy, and the locating precision is high.

A general approach is provided for producing devices that absorb optical photons (visible to near IR) and performs charge separation with a useful voltage between holes and electrons. These holes and electrons may be collected in electrodes for performing useful work outside the device. The described technology is generally based upon rectification of plasmons (collective electric excitations) generated by absorbing light with tuned metallic antennas. According to some embodiments, the present invention provides a spatial array of nanoscale conductors forming an optical rectenna that responds to an incident light source and generates a current offset that may be rectified by a rectification-inducing material. The present inventors foresee an extensive use of these optical rectennas as photovoltaic devices, as well as a wide interest in diverse fundamental research and applied technologies.

The invention discloses a U-shaped structure sapphire fiber grating temperature and stress sensor and a manufacturing method thereof. According to the U-shaped structure sapphire fiber grating temperature and stress sensor, the end face of a section of sapphire fiber is of a micropore structure, and a low-refractive-index cladding structure similar to photonic crystal fiber is formed; a section of long-period fiber grating enables MgO to be doped on the side face of the fiber by the adoption of an electromagnetic sputtering method so as to form MgAl2O4 crystals through reaction, the mechanical strength of the section of the fiber is changed, after grating is written into the fiber, two sections of grating are different in stress response, and the effect that temperature and stress are measured at the same time can be achieved. The U-shaped structure sapphire fiber grating temperature and stress sensor has the advantages of being simple in structure, wide in temperature measuring range, high in measuring accuracy and the like, and can be applied to temperature and stress measurement of rocket engines, optical cowlings and ultra-high temperature environments.

A signal modulation method for a receiving-end module of an induction type power supply system includes configuring a plurality of modulation periods corresponding to a modulation signal; performing modulation on a first terminal of an induction coil of the receiving-end module during the i<SP>th< / SP>modulation period among the plurality of modulation periods, wherein i is an odd number; and performing modulation on a second terminal of the induction coil of the receiving-end module during the j<SP>th< / SP>modulation period among the plurality of modulation periods, wherein j is an even number; wherein the second terminal does not undergo modulation when the first terminal is being modulated, and the first terminal does not undergo modulation when the second terminal is being modulated. The present invention also provides a signal rectification and modulation device.

An azeotrope separation process includes the steps: 1) adding raw materials into an extraction kettle, adding extraction agents, stirring the raw materials for a certain time, standing and separating the raw materials into a water phase and an oil phase; 2) transferring one of the water phase and the oil phase into a rectifying still, heating the raw materials by a rectifying still reboiler and enabling a vapor phase to rise into a rectifying tower; 3) condensing the vapor phase rising to the top of the rectifying tower into liquid, setting a suitable reflux ratio after total reflux stabilization, extracting over heads, then extracting products and finally extracting intermediate cut. The azeotrope separation process combines the advantages of batch rectification and extraction rectification, and is flexible in operation, good in stability, low in equipment investment and applicable to separation of a azeotropic system and a near-boiling system.

Methods and devices for low power optical detection and modulation in a slotted waveguide geometry filled with nonlinear electro-optic polymers are shown. Direct conversion of optical energy to electrical energy is enabled without external bias, via optical rectification, also enhancing electro-optic modulation.

A nanoscale electron shuttle with two elastically mounted conductors positioned within a gap between conductors produces asymmetrical electron conduction between the conductors when the conductors receive an AC signal to provide for rectification, detection and / or power harvesting.

This invention is a method for rectifying an input digital image including warped textual information. The method includes analyzing the input digital image to locate a plurality of local features, at least some of the local features including textual features. A sparse set of local image regions are located corresponding to reliable combinations of spatially-consecutive local features, and corresponding local orientations are determined. A global deformation function is formed by interpolating between the determined local orientations and is used to form a rectified image.

Apparatus for generating a microwave frequency comb (MFC) in the DC tunneling current of a scanning tunneling microscope (STM) by fast optical rectification, caused by nonlinearity of the DC current vs. voltage curve for the tunneling junction, of regularly-spaced, short pulses of optical radiation from a focused mode-locked, ultrafast laser, directed onto the tunneling junction, is described. Application of the MFC to high resolution dopant profiling in semiconductors is simulated. Application of the MFC to other measurements is described.

The invention provides a method and a device for generating high-energy terahertz pulses. A beam of high-energy femtosecond pulses is uniformly divided into two or more beams, the beams of high-energy femtosecond pulses are emitted to ZeTn crystals with identical parameters respectively, terahertz pulses are generated in the crystals by the aid of optical rectification processes of the femtosecond pulses respectively, and coherently combined terahertz pulses can be obtained by enabling the generated terahertz pulses to arrive at a detector simultaneously through time delay adjustment. According to the method and the device for generating the high-energy terahertz pulses, two or more stages of optical rectification processes are connected in parallel, and the terahertz pulses are output through coherent combination, so that the defect that laser energy cannot by fully used due to the fact that the damage threshold of a single crystal is low is overcome.

The invention relates to a method for generating and detecting terahertz pulses in real time. According to the technical scheme, the method comprises the steps that a metallic vapor vacuum arc method is carried out on lithium niobate single crystals grown through a crystal pulling method to obtain a lithium niobate single crystal sheet with copper injected, and the lithium niobate single crystal sheet is used as a terahertz radiation source (5); laser pulses generated by a titanium sapphire laser (3) enter the terahertz radiation source (5) in an incident mode, and terahertz pulses are generated through an optical rectification method; a terahertz time-domain pulse spectrum is obtained through an electro-optical sampling method, and finally fast Fourier transformation is carried out on the terahertz time-domain pulse spectrum through MatLab software installed in a computer to obtain a terahertz frequency-domain pulse spectrum. The method has the advantages that the device is simple, cost is low, the raw materials of the terahertz radiation source are rich and easy to obtain, and the terahertz pulses are high in generation efficiency.

The invention provides a bidirectional DC transformation circuit and a control method thereof. The circuit comprises a primary filtering capacitor, a primary full-bridge transformation circuit, a transformer, a secondary transformation circuit, a secondary filtering capacitor, an inductor and a controller; the inductor is connected in series between the transformer and the primary full-bridge transformation circuit; both the primary full-bridge transformation circuit and the secondary transformation circuit have functions of inversion and rectification; the secondary transformation circuit realizes rectification in the manners including full-wave rectification, dual-voltage rectification and full-bridge rectification; the front end rear ends of the bidirectional DC transformation circuit are connected with the DC side with a bidirectional capability; and the controller controls the ON sequence of the primary full-bridge transformation circuit and the secondary transformation circuit inthe forward / backward direction. According to the method, the voltage of the inductor and the primary voltage are added to the secondary side of the transformer, and thus, the output voltage is higherthan an original output voltage which is obtained by transforming an original input voltage according to the turn ratio of the transformer.

The invention discloses a THz wave generating device based on an optical rectification Cherenkov effect. The THz wave generating device based on the optical rectification Cherenkov effect is characterized in that the THz wave generating device comprises a femtosecond laser device, a cylindrical lens, a crystal-silicon prism array coupling body, a pneumatic infrared detector, a detecting unit and a time delay system. The femtosecond laser device is a full-automatic integrated broadband femtosecond laser device, the band width and the central wavelength of the femtosecond laser device can be adjusted automatically, the femtosecond laser device outputs optical pulses, the central wavelength of the optical pulses is 800nm, the optical pulses are in horizontal polarization, the space mode of the optical pulses is TEM00, the pulse width of the optical pulses is 18fs, and the diameter of beams is 2mm. The coupling body comprises a crystal and a plurality of blocky silicon prisms, the crystal is a slice-shaped cuboid, and all the silicon prisms are fixed on the upper surface and the lower surface of the crystal. The detecting unit comprises a detecting crystal and a phase-locked amplifier. The time delay system is matched with the detecting unit to carry out the measurement of the THz spectrum. The THz wave generating device based on the optical rectification Cherenkov effect improves the efficiency of converting pump light into THz waves, enlarges the effective acting distance of the optical pulses and the crystal, lowers the limitation to the coupling output of the THz waves, and improves the output efficiency of the THz waves.

The invention provides a thermionic triode. The thermionic triode comprises a first thermal pole, a second thermal pole and a thermal resistance regulating unit. The first thermal pole is made of a metallic material. The second thermal pole is made of a non-metallic material. The first thermal pole and the second thermal pole make close contact to form a thermal interface. The thermal resistance regulating unit is used for forming a regulation and control electric field at the thermal interface. The thermionic triode provided by the invention is simple in structure, effectively realizes thermal rectification and makes it possible to further manufacture various types of thermal logic devices.

A carrier frequency converter for converting a first information carrier frequency of a first carrier to a second information carrier frequency of a second carrier. The converter includes an input control optics assembly for receiving a first carrier and adjusting the first carrier in accordance with first desired frequency, polarization and beam propagation parameters. A non-linear optical medium provides optical rectification of an output of the input control optics assembly. An output control optics assembly receives an output of the non-linear optical medium and adjusts the output in accordance with second desired frequency, polarization and beam propagation parameters. The output of the output control optics is a second carrier having an information bandwidth equivalent to the information bandwidth of the first carrier.

The invention discloses an equal-scale optical rectification method for a panoramic optical image, which belongs to the fields of measurement of aviation and spaceflight images and aims at providing the equal-scale optical rectification method for the panoramic optical image by adopting pure optical rectification to directly rectify while the image is output. The equal-scale optical rectification method comprises the following rectification process that panoramic negative pieces enclose to form a circular arc shape, wherein the circle center surface of the circular arc faces to a rectification lens, and the circle center is positioned on a primary optical axis; photographic paper is in a hyperbolic curve shape; the scale of each point on the image formed on the photographic paper is identical and is the ratio the focus length to the height of the camera; an imaging light source can use a planar light source; the photographic paper is simultaneously exposed; the rectification is carried out by using different optical axial magnification powers; and the full piece is rectified into an image with the same scale as that of the optical axis. According to the equal-scale optical rectification method disclosed by the invention, the film type panoramic image is purely and optically rectified at equal scale (focus length of the camera / flying height) and a vertical image is formed after rectification. The equal-scale optical rectification method is mainly used for rectifying the negative piece image formed by a panorama camera.