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119 results about "Ultrashort pulse" patented technology

In optics, an ultrashort pulse of light is an electromagnetic pulse whose time duration is of the order of a picosecond (10⁻¹² second) or less. Such pulses have a broadband optical spectrum, and can be created by mode-locked oscillators. They are commonly referred to as ultrafast events. Amplification of ultrashort pulses almost always requires the technique of chirped pulse amplification, in order to avoid damage to the gain medium of the amplifier.

Light-weight micro-nano femtosecond waveguide etching process

The invention belongs to the technical field of waveguide engraving, and particularly relates to a lightweight micro-nano femtosecond waveguide engraving process, which comprises the following steps of: designing a laser scanning path according to the size and the shape of a required waveguide; adjusting parameters of a femtosecond laser, then scanning the material substrate along a laser scanning path, monitoring the position of a laser focus in real time, and adjusting laser parameters or scanning speed according to monitoring feedback; the controllable local refractive index change is generated in the material substrate by using the ultrashort pulse generated by the femtosecond laser, so that the direct waveguide structure formation without chemical etching is realized. By accurately controlling the position, the intensity and the scanning path of a laser beam, a waveguide element with high consistency and stability can be created on the submicron scale; according to the invention, while the preparation process is simplified, the precision and consistency of the waveguide structure are improved, the production cost is reduced, and the environmental pollution is reduced, so that the application requirements of high-performance photonic devices are met.
Owner:SHIYE TECHNOLOGY (SHENZHEN) CO LTD

While-drilling neutron porosity density measuring device and clock labeling method

The invention provides a while-drilling neutron porosity density measuring device and a clock labeling method, and the while-drilling neutron porosity density measuring device comprises an ultra-short pulse neutron generator which is used for generating ultra-short pulse neutrons with a specified time sequence; the fast neutron detector is used for monitoring the yield of the ultrashort pulse neutron generator; the thermal neutron detector group is used for recording thermal neutron flux; and the gamma detector group is used for recording inelastic gamma flux. According to the technical scheme, through the double-epithermal neutron double-gamma structure model, the influence of the stratum density on porosity measurement is effectively eliminated, and the measurement precision is improved.
Owner:CHINA NAT PETROLEUM CORP +1

Laser marking system and method for metal surface dazzling and coloring

The invention provides a laser marking system and method for metal surface dazzling and coloring, and relates to the technical field of metal surface laser precision machining.The system integrates a femtosecond laser, a nanosecond laser, an optical bread board, a lifting platform, an electric rotating slide, a scanning galvanometer, a focusing lens, a computer control system and an adsorption platform; two laser marking processes of colorful marking and coloring marking are innovatively combined; the femtosecond laser device achieves a colorful effect on the metal surface through ultrashort pulses, and the nanosecond laser device generates a colorful effect of various colors through the heat effect. Automatic switching of the two lasers is controlled through the lifting platform, the computer automatically recognizes the drawing and document process type, and multi-color-zone pattern marking is efficiently completed. The system is simple in structure and convenient to operate, can meet the high-precision double-process marking requirement of the metal surface, and is widely applied to the fields of consumer electronics, anti-counterfeiting technologies and the like.
Owner:HARBIN ENG UNIV

Laser rotary cutting precision machining system and method for micropores with large depth-diameter ratio

According to the large-depth-diameter-ratio micropore laser rotary-cutting precision machining system and method, light beam self-rotation and light beam scanning are achieved through a compact rotating assembly integrating a Dove prism and double reflectors, the off-axis angle and the off-axis amount are precisely regulated and controlled through deflection and movement of the reflectors, light beams are subjected to off-axis focusing through a focusing assembly, and the precision of laser rotary-cutting precision machining is achieved. Finally, a light path focusing mode of first converging and then off-axis focusing is formed, large-depth-diameter-ratio micropore machining is achieved, the aperture range is dozens of micrometers to several millimeters, and the maximum depth-diameter ratio can reach 15: 1 or above; the device is compact in structure, a complex adjusting system is not needed, the control mode is simple, high rotating speed can be achieved, ultra-short pulse time domain broadening is reduced through the double-reflector system, and machining of hole patterns such as steep straight holes and taper holes can be achieved.
Owner:LASER FUSION RES CENT CHINA ACAD OF ENG PHYSICS

Ultrashort pulses in LiDAR systems

LiDAR system and methods discussed herein use ultrafast light pulses. Use of ultrafast light pulses can result in reduced power consumption compared to longer length or conventional light pulses.
Owner:SEYOND INC

Transient fluorescence detection system with sub-gate pulse width time resolution

The invention provides a transient fluorescence detection system with sub-gate pulse width time resolution, and the system comprises a gate pulse generation system which is configured to generate a gate pulse needed by transient fluorescence detection based on first fundamental frequency light inputted into the gate pulse generation system; the ultrashort pulse generation system is configured to generate a few-period femtosecond pulse based on the second fundamental frequency light input into the ultrashort pulse generation system; the fluorescence generation system is positioned at the downstream of the ultrashort pulse generation system and is configured to excite a sample to generate fluorescence by taking a few-cycle femtosecond pulse as fluorescence excitation light; and the optical parametric fluorescence amplification system is positioned at the downstream of the gate pulse and the fluorescence and is configured to amplify the overlapped part of the fluorescence and the gate pulse in time and space through optical parametric amplification, so that transient fluorescence detection is realized. When an ultrashort pulse is used as an excitation light source, the optimal time resolution of transient fluorescence detection can reach 60 femtoseconds, the time resolution limit of optical parameter transient fluorescence detection can be broken through, and the sub-gate pulse width time resolution smaller than the gate pulse width is achieved.
Owner:INSTITUTE OF PHYSICS CHINESE ACADEMY OF SCIENCES

Compact high-power ultrashort pulse optical parametric amplification device

The invention provides a compact high-power ultrashort pulse optical parametric amplification device. The compact high-power ultrashort pulse optical parametric amplification device is sequentially provided with a slide array, a first blazed grating pair, a slit, a first reflector and a second blazed grating pair in the direction of an optical path, the femtosecond laser is controlled to perform spectrum broadening through the ultrathin slide array, the grating is used for pulse width compression, and the adjustable slit is used for bandwidth selection, so that large-range continuous tuning of optical parameters such as wavelength, pulse width, power and the like of the ultrafast femtosecond laser is realized; the device is especially suitable for high-power hundred-femtosecond and sub-hundred-femtosecond lasers. According to the device, incident femtosecond laser can be efficiently converted, the pulse width and the spectral bandwidth can be greatly and continuously adjusted, and compared with the mode that spectrum broadening is achieved through high-pressure inert gas through femtosecond laser, the laser output stability is remarkably improved; the method is particularly suitable for light source parameter tuning in ultra-high time resolution spectrum testing and ultrafast laser processing systems.
Owner:LIAOCHENG UNIV

2-micron wave band adjustable all-fiber high repetition frequency pulse light source generator

The invention discloses a 2-micron-waveband adjustable all-fiber high-repetition-frequency pulse light source generator, belongs to the technical field of laser light source manufacturing, and aims to solve the problem that an existing 2-micron-waveband passive all-fiber mode-locked pulse laser light source is difficult to give consideration to fs-magnitude narrow pulse width and ultra-short-cavity-length high-fundamental-frequency repetition frequency output. The laser comprises a semiconductor laser pumping source, a wavelength division multiplexer, an extrusion type polarization controller I, a polarization-maintaining highly-doped gain fiber, an extrusion type polarization controller II, a long cone region tapering micro-nano fiber, a 2 * 2 fiber coupler and a fiber Faraday mirror. According to the invention, the long-cone micro-nanofiber is introduced into the cavity, and the long-cone micro-nanofiber has the characteristic of high nonlinear coefficient, so that the cavity length can be greatly shortened, enough nonlinear phase shift can be accumulated, and fs-magnitude ultrashort pulse can be output. The device is low in loss, stable in performance and easy to integrate with other optical fiber systems. The laser can be applied to the fields of optical communication, non-metallic material processing, laser medical treatment, intermediate infrared laser pumping sources and the like.
Owner:CHANGCHUN UNIV OF SCI & TECH

Ultra-short pulse generation method and device based on single-mode and dual-mode fiber laser

The invention discloses an ultrashort pulse generation method and device based on a single-mode and dual-mode fiber laser. The method comprises the steps that pump light enters an erbium-doped fiber through a dual-mode wavelength division multiplexer, erbium ions are excited to an upper energy level to form population inversion, stimulated radiation is generated, and a laser signal is amplified; through the dual-mode optical fiber coupler, a small amount of laser is output to the outside of the cavity for measurement, and the remaining laser continues to oscillate in the cavity; the polarization state of the remaining laser in the resonant cavity is adjusted through a polarization controller so as to ensure that the laser is stably transmitted in the resonant cavity, and mode locking of the laser is realized by using a carbon nanotube saturable absorber so as to ensure that stable ultrashort pulses are generated; the laser passes through the dual-mode isolator to ensure that the light pulse runs unidirectionally in the resonant cavity and enters the dual-mode wavelength division multiplexer again to form circulation; and through periodic mode coupling, a stable mode-locked pulse is finally formed. The device is suitable for a few-mode optical fiber mode-locked laser, is simple in structure, is easy to construct and maintain, and is extremely high in stability and reliability.
Owner:WUHAN SPACE SANJIANG LITRI CO LTD

Pulse light generation device and pulse light generation method

A pulse light generation device 1 comprises: an oscillator 2 for oscillating an ultrashort pulse light L; a stretcher fiber 7 for widening the time width of the ultrashort pulse light L; a fiber amplifier 8 for amplifying the ultrashort pulse light L the time width of which has been widened by the stretcher fiber 7; and a compressor 9 for compressing the time width of the ultrashort pulse light L which has been amplified by the fiber amplifier 8. The stretcher fiber 7 is configured by combining a first fiber 71 for widening the time width of the ultrashort pulse light L with a first characteristic, and a second fiber 72 for widening the time width of the ultrashort pulse light L with a second characteristic which is different from the first characteristic.
Owner:HAMAMATSU PHOTONICS KK +1

Cross-octave super-continuum spectrum light source generation device and optical equipment

The invention relates to the technical field of super-continuum spectrum generation, and particularly provides a cross-octave super-continuum spectrum light source generation device and optical equipment, the cross-octave super-continuum spectrum light source generation device comprises a focusing lens and at least one group of solid structures, and ultrashort pulse fundamental frequency light enters the solid structures after being tightly focused; incident fundamental frequency light is firstly subjected to self-phase modulation in a first nonlinear action medium, a first super-continuum spectrum with a certain spectral width at the central wavelength of the fundamental frequency light is generated under the cross-phase modulation action, and except for the central wavelength, the first super-continuum spectrum is transmitted through a frequency doubling crystal; the spectrum at the central wavelength passes through a frequency doubling crystal to realize ultrashort pulse frequency doubling light, the frequency doubling light with high peak intensity generates a self-phase modulation effect in a second nonlinear action medium to generate a second super-continuum spectrum at the central wavelength of the frequency doubling light, and the two super-continuum spectrums form a cross-octave super-continuum spectrum light source; the super-continuum spectrum generation with high pulse energy is realized, the super-continuum spectrum generation range is further widened, and the multi-spectrum super-continuum spectrum generation is realized.
Owner:CHANGCHUN INST OF OPTICS FINE MECHANICS & PHYSICS CHINESE ACAD OF SCI

Wavelength variable light source and wavelength variable method

To allow a wavelength variable light source and a wavelength variable method that can tune the wavelength of the output light to reliably amplify the light over a wide wavelength range.SOLUTION: A wavelength variable light source 1 includes an optical output unit that outputs ultrashort pulsed light L and can variably change the wavelength of the output ultrashort pulsed light L, a second fiber amplifier 7 that amplifies the ultrashort pulsed light L output from the optical output unit, a filter 8 that filters the ultrashort pulsed light L amplified by the second fiber amplifier 7, and a third fiber amplifier 9 that amplifies the ultrashort pulsed light L filtered by the filter 8. The second fiber amplifier 7 has a higher gain on the short wavelength side than on the long wavelength side. The third fiber amplifier 9 has a higher gain on the long wavelength side than on the short wavelength side. The filter 8 attenuates the amplified spontaneous emission light.SELECTED DRAWING: Figure 1
Owner:HAMAMATSU PHOTONICS KK +1

Femtosecond laser additive manufacturing method for lithium-loving microstructure on surface of copper foil current collector for metal lithium negative electrode

The invention relates to the technical field of battery materials, in particular to a method for manufacturing a lithium-loving microstructure on the surface of a copper foil current collector for a metal lithium negative electrode through femtosecond laser additive manufacturing. Based on the characteristics of ultrashort pulse, ultrahigh peak power and high precision of femtosecond laser, the femtosecond laser is focused on the surface of a copper foil current collector coated with a metal salt solution, and the power and repetition frequency of the femtosecond laser are regulated and controlled, so that the metal salt is decomposed into nano metal particles which are locally sintered and fused on the surface of the copper foil current collector; the moving path of the femtosecond laser micro-nano moving table is controlled, the lithium-loving metal microstructure is manufactured on the surface of the copper foil current collector in an additive mode, ordered and compact deposition of metal lithium can be guided, growth of lithium dendrites can be remarkably inhibited, and the reversible capacity and cycling stability of the metal lithium negative electrode can be improved. The method is simple in technological process, high in preparation efficiency and high in repeatability, and wide application prospects are provided for practicability of the high-energy-density metal lithium battery.
Owner:INST OF METAL RESEARCH - CHINESE ACAD OF SCI

Apparatus and method for measuring damage limit level of laser gain medium

ActiveKR102992773B1Light beamLaser light
The present invention relates to a device for measuring the damage limit of a laser amplification medium and a method for measuring the damage limit. A device for measuring the damage limit of a laser amplification medium according to one embodiment of the present invention may include: an ultrashort pulse generator that generates laser light having an ultrashort pulse; an amplification unit that irradiates the laser light onto a laser amplification medium to amplify the output of the laser light; and a beam measurement unit that generates a beam profile of the laser light output from the amplification unit and measures a damage threshold of the laser amplification medium by utilizing a change in the beam profile according to a Kerr lens phenomenon.
Owner:KOREA ELECTROTECH RES INST

Rotating fiber based wavelength tunable dual-color cavity ultrafast fiber laser and control method

ActiveCN122068345BGainDual wavelength
This invention discloses a wavelength-tunable dual-cavity ultrafast fiber laser based on rotating optical fibers and its control method, relating to the field of laser technology. The dual-cavity ultrafast fiber laser of this invention integrates a wavelength division multiplexer within a dual-ring resonant cavity, structurally integrating two wavelength channels, each containing an independent gain fiber, to achieve dual-color soliton output and reduce gain competition. By setting an adjustable rotating fiber filter, consisting of a polarization controller, rotating optical fibers, and a polarization-dependent isolator, in the multiplexing section, the center wavelength of both wavelengths is tunable. Simultaneously, the two sub-cavities share the same saturable absorber to achieve passive synchronous mode-locking, and a delay line is introduced into one of the channels to adjust the equivalent cavity length, achieving repetition frequency matching and timing alignment between the two sub-cavities, thereby obtaining stable, tunable, and synchronous dual-wavelength ultrashort pulse output.
Owner:NANJING UNIV OF INFORMATION SCI & TECH

Multi-channel feature inversion method and device for non-Gaussian ultrashort pulse

The invention provides a non-Gaussian ultrashort pulse-oriented multi-channel feature inversion method and device, and the method comprises the steps: obtaining a first FROG trace graph, carrying out the multi-channel feature extraction of the first FROG trace graph, and generating a three-channel input feature graph; inputting the three-channel input feature map into an intensity prediction network, outputting a predicted pulse intensity envelope, inputting the first FROG trace map into a phase prediction network, outputting predicted pulse phase distribution, and filtering the predicted pulse intensity envelope and pulse phase distribution to smooth noise; and reconstructing a complex electric field based on the filtered intensity and phase, regenerating to obtain a second FROG trace graph, and calculating an error index between the first FROG trace graph and the second FROG trace graph, the error index comprising an FROG error and an intensity correlation coefficient. According to the invention, the requirement of an advanced ultrafast laser system for high-precision online diagnosis of non-ideal pulses is met, and key technical support is provided for online diagnosis and closed-loop control of the advanced ultrafast laser system.
Owner:BEIJING INFORMATION SCI & TECH UNIV

All-polarization-maintaining fiber femtosecond laser based on mode-locking start facilitating structure

The application relates to a full-polarization-maintaining fiber femtosecond laser based on a mode-locking starting promotion structure. The laser comprises a nonlinear amplification ring mirror with a double-path gain fiber, can realize continuous adjustment of a phase difference, introduces a nonlinear phase shift related to laser pulse intensity, reduces a mode-locking threshold of the nonlinear amplification ring mirror laser, improves self-starting mode-locking capability of the laser, and outputs high-power and high-stability ultrashort pulses; a non-reciprocal phase shift element introduces a linear phase shift bias for clockwise and counterclockwise propagation pulses; a linear arm introduces an optical element with a dispersion compensation function, ensures compactness of the oscillator, is used for outputting pulses, simultaneously provides seed pulse pre-chirp management for subsequent higher-power amplification, and realizes flat wide spectrum. The laser adopts a full-polarization-maintaining fiber structure, has good self-starting mode-locking characteristics, is beneficial to pulse filtering and shaping, and simultaneously has the advantages of compact structure, good stability, high damage threshold, high output power and low noise.
Owner:HUAZHONG UNIV OF SCI & TECH

System and method for compressing short or ultra-short light pulses, and associated light-pulsed laser system

Disclosed is a system for compressing short or ultra-short light pulses emitted by a light source. The compression system includes: —a first non-linear light pulse compression module including a multi-pass cell, the multi-pass cell including a first non-linear optical medium; and —a second non-linear light pulse compression module including a capillary filled with a gaseous second non-linear optical medium, and a compressor arranged at the output of the capillary, the first non-linear compression module and the second non-linear compression module being arranged in series on the path of a source light beam of source light pulses. Also disclosed is a light-pulses laser system and to a method for compressing short or ultra-short light pulses.
Owner:CENT NAT DE LA RECH SCI (C N R S) +1

Electrode sheet die-cutting device

The electrode sheet punching device includes a laser processing table (110), a laser cutting machine (120), and a flaw detection module (130). The laser processing table (110) is located below the electrode sheet (200) and has a plurality of suction holes (111) that can suck and fix the electrode sheet (200) to the surface of the laser processing table (110). The laser cutting machine (120) is located facing the laser processing table (110) and emits ultrashort pulsed ultraviolet light toward the electrode sheet (200) to cut the electrode sheet (200). The flaw detection module (130) is located downstream of the laser cutting machine (120) along the flow path of the electrode sheet (200) and is used to detect the appearance of the electrode sheet (200) cut by the laser cutting machine (120). This embodiment prevents the electrode sheet (200) from moving and shifting, and also prevents dimensional fluctuations due to deformation of the electrode sheet (200) itself, thereby ensuring stable and high cutting quality for the electrode sheet (200). Furthermore, by using ultrashort pulse ultraviolet light to cut the electrode sheet (200), low-temperature processing of the electrode sheet (200) is achieved, preventing deformation and carbonization of the polymer layer of the composite current collector due to high cutting temperatures, and achieving higher cutting quality.
Owner:YANGZHOU NANOPORE INNOVATIVE MATERIALS TECH LTD

Dual-wavelength femtosecond laser direct-writing miniaturized precursor ceramic high-temperature thin film sensor

The invention discloses a dual-wavelength femtosecond laser direct-writing miniaturized precursor ceramic high-temperature thin film sensor, and relates to the technical field of high-temperature thin film sensor manufacturing. Depositing the precursor functional slurry on the surface of a substrate layer by layer by adopting additive manufacturing processes such as blade coating, direct writing and the like, and performing pyrolysis to form an amorphous ceramic multilayer film; based on a dual-wavelength femtosecond laser micro-nano processing platform, the device comprises 1035nm / 343nm double light sources, a light path transmission system and a motion platform, and the characteristics of femtosecond laser ultrashort pulse and high peak power density are utilized to realize submicron precision graphical processing of a precursor ceramic film. And the area of the high-temperature film sensor unit is reduced from the square millimeter level of the traditional process to the square micron level. The method has the advantages of dual-wavelength laser collaborative processing, multi-layer film compatibility and the like, overcomes the disadvantages of large size and poor forming precision of a traditional additive manufacturing precursor ceramic film sensor, and provides a new normal form for integrated manufacturing of a micro sensor array serving in an extreme environment.
Owner:XIAMEN UNIV

High energy thulium-doped fiber laser based on self-mode-locking and dispersion management

The application relates to the field of optical information technology, and particularly relates to a high-energy thulium-doped fiber laser based on self-locking mode and dispersion management technology, wherein a pump laser is connected with one end of a pump protector, the other end of the pump protector is connected with an a end of a wavelength division multiplexer, a b end and a c end of the wavelength division multiplexer are respectively connected with an i end of a three-port circulator and one end of a thulium-doped gain fiber, the other end of the thulium-doped gain fiber is connected with a d end of an optical coupler, an e end of the optical coupler is connected with one end of a polarization controller, the other end of the polarization controller is connected with one end of a single-mode optical fiber, the other end of the single-mode optical fiber is connected with a g end of the three-port circulator, an h end of the three-port circulator is connected with one end of a collimator, and the other end of the collimator is provided with a dispersion compensation assembly, high-energy ultrashort pulses can be generated, the structure is optimized, and the manufacturing cost is reduced.
Owner:SANMING UNIV

Ultra-short pulse dynamic regulation and control device and method based on double acousto-optic deflectors

The invention discloses an ultrashort pulse dynamic regulation and control device and method based on double acousto-optic deflectors, and belongs to the technical field related to laser. The device comprises an acousto-optic deflector group and a 4f optical system, the 4f optical system is formed by biconvex lenses with two times of focal length, and the optical axis is parallel to the horizontal plane; the 4f optical system changes the positive and negative of the symbols of acousto-optic effect group delay dispersion and improves the range of group delay dispersion; the acousto-optic deflector group is composed of two acousto-optic deflectors which are arranged in parallel and in opposite directions, and the two acousto-optic deflectors are located on the two sides of the 4f optical system respectively and are both perpendicular to the optical axis. First polarized light of an input light beam is converted into second polarized light through the first acousto-optic deflector, the second polarized light is converted into first polarized parallel light beams through the 4f optical system and the second acousto-optic deflector, and an output light beam is obtained. The acousto-optic deflector group provides continuously adjustable group delay dispersion and regulates and controls the pulse width of an output light beam. The device is low in cost, is simple to operate, and dynamically regulates and controls the pulse width of the output light beam.
Owner:HUAZHONG UNIV OF SCI & TECH

Ultra-short pulse wavelength real-time regulation and control system and method based on phase modulation

The invention belongs to the technical field of ultra-short pulse wavelength real-time regulation and control methods, and particularly relates to an ultra-short pulse wavelength real-time regulation and control system and method based on phase modulation, and the system is composed of a pulse light source, a polarization controller, a signal generator and a phase modulator. The pulse light source is used for providing an ultrashort pulse sequence with stable repetition frequency, the polarization controller is used for adjusting the polarization state of pulses, the signal generator is used for generating radio frequency electric signals, and the phase modulator is used for changing the phase distribution of the pulses under the driving of the radio frequency electric signals to cause pulse light frequency shift. Therefore, the real-time and rapid regulation and control of the spectral wavelength can be realized. According to the invention, real-time and rapid regulation and control of the ultrashort pulse wavelength can be realized, the operation is simple and flexible, and the method has important application value in the fields of optical communication and the like.
Owner:NORTHWEST UNIV

Neutron Analytical Physics Testing System and Method

This invention discloses a neutron analysis physics testing system and method, belonging to the field of nuclear physics testing technology. The system includes: a high-speed synchronous pulse generator for generating pulse signals with multiple modulation sequences; an ultrashort pulse neutron generator for emitting short pulse neutron rays with specified parameters onto a sample; a neutron detector for acquiring secondary neutron signals; a gamma detector for acquiring characteristic gamma signals generated by neutron-excited probes of the sample; a safety control module for controlling the operating state of the ultrashort pulse neutron generator; and a data processing device for real-time collection and summarization of neutron signals and characteristic gamma signals based on the timing of the pulse signals with multiple modulation sequences. This system reduces time window drift and measurement errors, and activates the ultrashort pulse neutron generator only when a gate signal allows, improving the accuracy, safety, and stability of geological physics parameter measurements.
Owner:HEFEI INSTITUTE OF PHYSICAL SCIENCE CHINESE ACADEMY OF SCIENCES

Real-time vector analysis method and device for detecting optical signal with bandwidth greater than 1 THz

A real-time vector analysis method for detecting an optical signal with a bandwidth greater than 1 THz includes: mapping, by a time-lens focusing system, a spectrum of a signal under test to different temporal location information; obtaining, by fully broadening an ultrashort pulse by a dispersion, a time domain spectrum of the ultrashort pulse to form a chirped swept frequency source; inputting an out of the signal under test after passing through the time-lens and the chirped swept frequency source to a coherent receiver to realize an interference process and a conversion of an optical signal to an electrical signal, and recovering an intensity information and a phase information of frequency domain of the signal under test from the electrical signal by data acquisition and processing; then recovering a full-field information of time domain of the signal under test by a Fourier inverse transform.
Owner:HUAZHONG UNIV OF SCI & TECH

A molten pool pore inhibition method based on ultrafast laser liquid area impact regulation

The application discloses a kind of based on ultrafast laser liquid area impact regulation and control's molten pool pore inhibition method, belong to additive manufacturing and welding technical field.The method first establishes the three-dimensional space coordinates of ultrafast laser focus and molten pool liquid area servo correlation;After dynamic molten pool is formed by heat source, ultrafast laser is accurately focused in the molten pool liquid area pore prone position, and plasma shock wave induced by ultrafast laser ultrashort pulse acts on liquid metal.The method breaks through the inherent convection state of molten pool by shock wave and increases local flow rate, while high-frequency impact shears large-volume bubble into micro-nano bubble, and promotes micro-nano bubble collision and rapid floating, realizes the multi-mechanism synergistic exhaust of active interference-flow field-large bubble shear crushing-micro-nano bubble merging and floating, and completely drives away bubble from molten pool liquid area before solidification front arrives.The application significantly improves the density and mechanical properties of formed piece and welded joint.
Owner:BEIJING UNIV OF TECH

Optoelectronic oscillator and signal processing method

PCT designated stageWO2026045595A1Solid masersPulse sequenceMechanical engineering
An optoelectronic oscillator (100) and a signal processing method, which relate to the technical field of optoelectronics. In the optoelectronic oscillator (100), an electro-optical modulator (110), an optoelectronic detector (120), a first filter (130) and a power divider (140) form an optoelectronic oscillation loop. Compared with a conventional single-passband filter, the first filter (130) in the optoelectronic oscillation loop has an additional low-frequency passband, and thus can excite a pulse train of the low-frequency passband and a pulse train of a bandpass band in the optoelectronic oscillation loop. Since the oscillation of a pulse signal can automatically narrow a pulse train to form an ultrashort pulse train, when the pulse train excited by the bandpass band has undergone pulse narrowing by means of an oscillation mechanism in the optoelectronic oscillation loop, the pulse train excited by the low-frequency passband may further undergo pulse narrowing, such that the optoelectronic oscillator (100) can generate a microwave pulse train which is shorter than that of a conventional optoelectronic oscillator, that is, an ultrashort microwave pulse train.
Owner:HUAWEI TECH CO LTD

Uranium mine logging instrument based on ultrashort pulse neutrons and working method thereof

The invention discloses a uranium mine logging instrument based on ultrashort pulse neutrons and a working method thereof, and relates to the field of uranium mine exploration logging. The logging instrument comprises a control communication short section, an ultrashort pulse neutron generator used for emitting fast neutron pulses with the pulse width smaller than 1 microsecond to a stratum, a shielding body and a double-thermal-neutron detection assembly used for detecting thermal neutrons and epithermal neutrons on measuring points consistent in space, all of which are sequentially arranged in the axial direction of the logging instrument. The gamma detector is used for detecting inelastic scattering gamma rays emitted by stratum elements and capturing gamma rays, and the fast neutron detector is used for detecting and outputting source intensity monitoring signals of fast neutron pulses in real time. According to the logging instrument, the ultra-short fast neutron pulse is emitted, the neutron yield is detected in real time, the neutron time spectrum and gamma-ray energy spectrum multi-dimensional information with an accurate timestamp are obtained in a combined mode, high-precision and anti-interference inversion is conducted on the stratum uranium content, and stratum information is obtained efficiently and accurately.
Owner:HEFEI INSTITUTE OF PHYSICAL SCIENCE CHINESE ACADEMY OF SCIENCES

Laser grinding combined machining preparation method for wear-resistant and friction-reducing surface of titanium alloy

The invention discloses a laser grinding combined machining preparation method for a titanium alloy wear-resisting and friction-reducing surface. The laser grinding combined machining preparation method comprises the following steps that 1, grinding and polishing are conducted, specifically, a titanium alloy sample is subjected to ultrasonic cleaning after being subjected to polishing treatment; the titanium alloy sample is placed on an ultra-short pulse laser machining platform, laser modification treatment is conducted on the surface of the titanium alloy sample, and the titanium alloy sample surface material is subjected to in-situ modification under the laser effect to generate a TiO2 ceramic modified layer; the titanium alloy sample is placed on an abrasive belt grinding machining platform, grinding and polishing are conducted on the titanium alloy sample, defects on the surface of the TiO2 ceramic modified layer are removed, and a smooth surface is obtained; and 4, ultrasonic cleaning is conducted, specifically, the titanium alloy sample is subjected to ultrasonic cleaning, and the titanium alloy sample with the wear-resisting and friction-reducing surface is obtained. The hardness and wear resistance of the titanium alloy wear-resistant and friction-reducing surface can be improved, the friction coefficient of the titanium alloy wear-resistant and friction-reducing surface is reduced, the service life is prolonged, and the reliability is improved.
Owner:CHONGQING UNIV