200 results about "Femtosecond pulsed laser" patented technology

The invention relates to methods of writing a light-guiding structure in a bulk glass substrate. The bulk glass substrate is preferably made from a soft silica-based material having an annealing point less than about 1380°K. A pulsed laser beam is focused within the substrate while the focus is translated relative to the substrate along a scan path at a scan speed effective to induce an increase in the refractive index of the material along the scan path. Substantially no laser-induced physical damage of the material is incurred along the scan path. Various optical devices can be made using this method.

Waveguides produced in bulk glass using femtosecond pulsed lasers have diameters and refractive index profiles that are manipulated by additional motions or beams. For example, spot focuses of the femtosecond pulsed lasers trace overlapping or widened tracks by superimposing additional relative motions between the spot focuses and the bulk glass. Additional femtosecond pulsed beams can also be used to produced widened waveguides.

An apparatus and method for measuring and mapping thermal conductivity and thermal diffusivity at micrometer scale resolution. The apparatus and method utilize a mode-locked femtosecond pulsed laser in a pump-probe configuration to analyze time-domain thermoreflectance of a specimen to evaluate its thermal conductivity in micro-scale, so that, if desired, an image of thermal conductivity distribution of micro-scale regions may be obtained therefrom. A multi-layer, complete three-dimensional model that takes into account the entire three-dimensional heat flow in cylindrical coordinates enables micro-scale measurements to be made at an accuracy of about 90% of well-accepted values.

The invention discloses a laser combined machining and profile modification method of a micro deep borehole without a recast layer. The method of the invention includes the following steps: first, a micro deep cooling borehole of a turbine blade is roughly machined by high power laser or electric sparks, and the like; the allowance for finish of the aperture is more than the thickness of the recast layer produced by using the machining method; and femtosecond laser is used for the secondary finish machining and profile modification of the micro deep cooling borehole; while femtosecond impulse laser is used for performing the finish machining and profile modification of the primarily machined micro deep borehole, under the precondition of guaranteeing the laser energy acting with the recast layer of a workpiece is higher than the ablation threshold of the material, a light beam is inclined for certain angle according to the spiral drilling mode; and the recast layer of the internal wall of the borehole is machined to remove erosion and profile modification by combining the method of lengthening the focal depth by a long focus lens. The concept of the combined machining method and the specific machining technology are used for solving the high-efficiency and high-precision machining problems of micro deep borehole groups of turbine blades.

The invention relates to a method for improving the machining efficiency of micro-channel preparation through femtosecond laser, which belongs to the technical field of femtosecond laser application. The method includes the steps: firstly, generating the femtosecond pulse laser by the aid of a femtosecond laser system, adjusting energy by means of combination of a half wave plate and a polarizing film and modulating the femtosecond laser into femtosecond interval pulse sequence by the aid of a pulse shaper; secondly, reflecting the pulse sequence laser obtained in the first step to an objective lens for focusing through a reflector, realizing imaging by the aid of a CCD (charge coupled device) and a lighting source, moving a six-dimensional precision electric control platform and positioning a laser focus on the lower surface of a sample horizontally placed on the six-dimensional precision electric control platform; and thirdly, controlling the six-dimensional precision electric control platform to move along a laser propagation direction by the aid of a computer to machine a micro-channel on the sample. As the femtosecond laser is modulated into the femtosecond interval pulse sequence by the aid of the pulse shaper, the micro-channel preparation efficiency is improved. Moreover, introduction of a vibration source is omitted, so that controllability of precision machining cannot be reduced.

The invention relates to the field of optics, and provides a coherent anti-stokes Raman scattering spectrum detection and microimaging system which comprises a femtosecond pulse laser device, a beam divider, a pohotonic crystal fiber, a narrow bandpass filter, a delay unit, a beam combiner and a detector, wherein the beam divider is used for dividing femtosecond pulse laser into a first light beam and a second light beam; the pohotonic crystal fiber is used for pumping the first light beam to output super-continuum spectrum laser of which the pulse width is picosecond grade as Stokes light; the narrow bandpass filter is used for filtering the second light beam to increase the pulse width to be approximate to that of the super-continuum spectrum laser as pumping light and detection light; the delay unit is used for synchronizing the stokes light, the pumping light and the detection light; the beam combiner is used for combining the Stokes light, the pumping light and the detection light into a third light beam; the detector is used for detecting a correlated anti-Stokes Raman scattered spectrum. By adopting the coherent anti-stokes Raman scattering spectrum detection and microimaging system, simultaneous imaging of multiple chemical bands can be rapidly achieved, a super-continuum spectrum light source is lowly required, a complete CARS (Coherent Anti-Stokes Raman Scattering) spectrum can be obtained, the light beam utilization efficiency can be maximized, and the spectral resolution of CARS imaging can be improved.

The invention relates to methods of writing a light-guiding structure in a bulk glass substrate. The bulk glass substrate is preferably made from a soft silica-based material having an annealing point less than about 1380° K. A pulsed laser beam is focused within the substrate while the focus is translated relative to the substrate along a scan path at a scan speed effective to induce an increase in the refractive index of the material along the scan path. Substantially no laser-induced physical damage of the material is incurred along the scan path. Various optical devices can be made using this method.

A new technique and Method of Direct Coulomb Explosion in Laser Ablation of Semiconductor Structures in semiconductor materials is disclosed. The Method of Direct Coulomb Explosion in Laser Ablation of Semiconductor Structures provides activation of the “Coulomb explosion” mechanism in a manner which does not invoke or require the conventional avalanche photoionization mechanism, but rather utilizes direct interband absorption to generate the Coulomb explosion threshold charge densities. This approach minimizes the laser intensity necessary for material removal and provides optimal machining quality. The technique generally comprises use of a femtosecond pulsed laser to rapidly evacuate electrons from a near surface region of a semiconductor or dielectric structure, and wherein the wavelength of the laser beam is chosen such that interband optical absorption dominates the carrier production throughout the laser pulse. The further application of a strong electric field to the semiconductor or dielectric structure provides enhancement of the absorption coefficient through a field induced redshift of the optical absorption. The use of this electric field controlled optical absorption is available in all semiconductor materials and allows precise control of the ablation rate. When used in conjunction with nanoscale semiconductor or dielectric structures, the application of a strong electric field provides for laser ablation on sub-micron lateral scales.

The invention discloses a miniature dual-photon micro-imaging device and method, and a living sample behavior imaging system. The miniature dual-photon micro-imaging device comprises a femtosecond pulse laser, a femtosecond pulse laser modulator, a miniature probe and a fluorescent output optical fiber, wherein the femtosecond pulse laser is used for generating laser with a wavelength of 920 nanometers; the femtosecond pulse laser modulator is used for receiving the laser outputted by the femtosecond pulse laser, pre-chirping the pulse width of the compensated laser to a preset value and outputting; the miniature probe comprises a scanning imaging part, the scanning imaging part is used for receiving the laser outputted by the femtosecond pulse laser modulator, and the laser is used for scanning tissues inside a living sample to excite the live sample to generate a fluorescent signal; the fluorescent output optical fiber is used for receiving and outputting the fluorescent signal outputted by the scanning imaging part. The miniature dual-photon micro-imaging device disclosed by the invention can stably observe the activities of dendrites and dendrite spines of an unrestrained animal in a natural physiological environment.

The invention relates to methods of writing a light-guiding structure in a bulk glass substrate. The bulk glass substrate is preferably made from a soft silica-based material having an annealing point less than about 1380 DEG K. A pulsed laser beam is focused within the substrate while the focus is translated relative to the substrate along a scan path at a scan speed effective to induce an increase in the refractive index of the material along the scan path. Substantially no laser-induced physical damage of the material is incurred along the scan path. Various optical devices can be made using this method.

The invention discloses a nonlinear polarization rotary mode-locked and wavelength tunable type L-waveband femtosecond Er-doped fiber laser and belongs to wavelength tunable type femtosecond pulse lasers. The nonlinear polarization rotary mode-locked and wavelength tunable type L-waveband femtosecond Er-doped fiber laser comprises a pumping source and an optical fiber ring cavity, wherein the optical fiber ring cavity is formed by connecting a wavelength division multiplexer, Er-doped fibers, an optical fiber isolator, an optical fiber polarizer, an optical fiber coupler and optical fibers used in a polarization controller, the pumping source is connected with the pumping port of the wavelength division multiplexer, a public port of the wavelength division multiplexer is connected to the 80% output port of the optical fiber coupler after passing through the Er-doped fibers, the optical fiber isolator and the optical fiber polarizer in sequence, and the input end of the optical fiber coupler is connected to a signal port of the wavelength division multiplexer through the polarization controller; the optical fiber isolator is connected with the optical fiber polarizer through dispersion compensation fibers, and the other devices are connected through single-mode optical fibers. The nonlinear polarization rotary mode-locked and wavelength tunable type L-waveband femtosecond Er-doped fiber laser has the advantages that the structure is simple and reliable, maintenance is convenient, external signal modulation is not needed, self-starting mode locking can be achieved, output pulses are narrow, the working performance is excellent, cost is low, and operation is easy.

The invention provides a light-emitting diode (LED) substrate lift-off method, which comprises the steps of: providing an LED substrate, wherein the LED substrate comprises a substrate and an epitaxial layer which is arranged on the substrate; bonding the epitaxial layer on a transfer substrate; thinning the substrate in the LED substrate by adopting a femtosecond laser system, wherein the femtosecond laser system focuses femtosecond pulse laser in the substrate, a light spot formed through focusing is a linear light spot and the length of the linear light spot is larger than or equal to the diameter of the LED substrate; and removing the remaining substrate by adopting a physicochemical polishing method to expose the epitaxial layer. The LED substrate lift-off method has the advantages that the heat produced in the lift-off process can be prevented from damaging the epitaxial layer, the rate of non-defective products is improved and the luminous efficiency is improved.

The present invention relates to the optical coherent tomographic (OCT) imaging technology. Technologically, the present invention features that longitudinal resolution of OCT is raised through either utilziing dispersive element or blocking element to change the spectrum shape of input light source or utilizing one blocking element to change the spectrum shape of reference arm returned light. The present invention may be used for the OCT system with femoto second-level laser or SLD light source. The method is simple and may be used to raise the longitudinal resolution of OCT system for 20 microsecond to 14 microsecond.

The invention provides a high-speed multi-width terahertz time-domain spectral imager, aiming at problems in the prior art. Femtosecond laser pulse is divided, and certain time delay exists among pulses; then the sequence is divided into two ways, one way is used for generating a terahertz pulse sequence, and the other way is used for generating probe light pulse with an oblique leading edge through an oblique leading edge pulse light generating device, so that the one-time transient measurement of the terahertz pulse is realized; a signal acquiring and processing module is combined for imaging each probe pulse, so that the wave form information of each sub pulse of a plurality of terahertz pulse sequences can be obtained. According to the invention, the wave form information of a plurality of sub pulses of the terahertz pulse sequence is measured by a femtosecond pulsed laser device, a negative chirp pulse light generating device, a light splitting delay device, a terahertz generating device, an oblique leading edge pulse light generating device, an electrooptical effect crystal and the signal acquiring and processing module.

The invention relates to a two-tone femtosecond laser collinear pumping detecting thermal reflection system which comprises a polarization output pulse laser, a wave plate, a beam splitting element, a reflecting mirror, an electro-optical modulator, a frequency doubling crystal, an optical filter, a beam expander, an electronic control displacing platform, a cold-light mirror, a fixing adjusting frame, a focusing lens, a photoelectric detector and a filter amplifier, wherein the polarization output pulse laser is used for outputting a pulse laser; the wave plate is used for causing the laser to rotate along a polarization direction; the laser beam is divided into two mutually vertical beams along the polarization direction by the beam splitting element; the laser beam is received and reflected by the reflecting mirror; the laser beam is modulated by the electro-optical modulator; the frequency doubling crystal is used for causing the laser to generate second harmonics; the laser within an appointed wavelength interval is filtered by the optical filter; the diameter of the laser beam is expanded by the beam expander; the electronic control displacing platform can move back and forth; the laser beams with different wavelengths are combined by the cold-light mirror; a sample is fixed by the fixing adjusting frame; the laser is irradiated on the surface of the sample by the focusing lens; the photoelectric detector is used for receiving the laser passing through the optical filter and generating an electric signal; and the signal of the photoelectric detector is amplified by the filter amplifier. According to the two-tone femtosecond laser collinear pumping detecting thermal reflection system, femtosecond pulse lasers with different wavelengths are applied to pumping light and detecting light; the pumping light after being subjected to frequency doubling is filtered by the optical filter with high selective permeability; the interference of the pumping light to a detecting signal is avoided; and the accurate high-efficient measurement is realized.

The invention relates to an accessory combined type terahertz time-domain spectroscopy system. A femtosecond pulse laser device radiates linearly polarized ultra-short pulse laser, the ultra-short pulse laser passes a laser plane mirror and then passes a half-wave plate and a polarization beam splitter, and pumping light and detection light which are perpendicular to each other are obtained; the pumping light enters a terahertz emission module, and parallel terahertz waves are radiated and enter a terahertz detection module through a testing device with a sample; the detection light passes a quarter-wave plate and reaches a time delay module, the detection light is returned along the original path after being reflected by a laser retroreflection mirror, then the detection light passes the time delay module and the quarter-wave plate again, the polarization state of the detection light is converted to be consistent with that of the pumping light, the detection light is reflected by the polarization beam splitter to a foldable mirror, and then the detection light is reflected by the laser plane mirror to enter the terahertz detection module. The testing device with the sample is designed for multifunctional accessories, so functions of transmission and reflection, parallel and focusing, attenuated total reflection, reflection measurement at any angle, imaging and the like can be easily switched and used.

The invention provides a dual-color two-photon fluorescence imaging method and a device, which uses six dual-color beams for emitting along plus and minus X, plus and minus Y, plus and minus Z six directions into the sample 3, thereby forming a three-dimensional lattice for exciting fluorescence, and uses a two-dimension small hole array 6 for filtering background fluorescence in the detecting light path, uses femtosecond pulsed laser with two different kinds of frequencies for composing a dual-color beam, wherein the two are coaxial, and the wavelengths are lambada 1 and lambada 2 respectively, moreover, lambada 1 is equal to lambada 2. Two kinds of light with different wavelength form two different three-dimensional lattice structures in the sample 3, and delay line 10 is modulated for causing the six beams to have the same optical path, only in the zone where two kinds of three-dimensional lattices coincide mutually, the dual-color two-photon fluorescence can be excitated. The device provided by the invention can effectively improve resolution response and imaging speed of three-dimensional imaging, and can be conveniently operated.

The invention discloses a manufacturing method for minuteness spherical titanium powder, and belongs to the technical field of metal and alloy powder manufacturing. The manufacturing method includes the steps that titanium sponge serves as a raw material to be manufactured into a bar or a wire; in a melting chamber, under the vacuum condition, double-femtosecond pulse lasers are used for inducing, heating and melting, and the melted raw material is poured into a tundish; the raw material is transferred into an atomizing chamber, under the vacuum condition, inert gas led into a centrifugal stem bar breaks titanium melt; further breaking is carried out through a laval spraying nozzle, and micron-order titanium liquid is manufactured; and finally, the micron-order titanium liquid is contained in an argon filling medium tank to be solidified and cooled, and the minuteness spherical titanium powder can be obtained after screening is carried out. The double-femtosecond pulse lasers are used for rapidly and efficiently melting titanium in a pure manner, and the even, stable and continuous alloy liquid flow can be formed; in addition, the melting and pulverization efficiency is high, and the atomizing yield and the powder yield of the metal powder are improved; and the manufactured minuteness spherical titanium powder is high in degree of sphericity and low in oxygen content.

The invention provides a system and method for machining an LED (light-emitting diode) substrate by laser. The system comprises a femtosecond pulse seed laser source, a laser amplifying and beam expanding device and a bearing component, wherein the laser amplifying and beam expanding device carries out energy amplification, beam expansion and line focalization on femtosecond pulse laser given out by the femtosecond pulse seed laser source and outputs a linear light spot; the length of the linear light spot is more than or equal to the diameter of the LED substrate; the bearing component is used for bearing the LED substrate; and the linear light spot is focalized in the LED substrate or on the surface of the LED substrate. By using the system and the method, the LED substrate can be machined by adopting the femtosecond laser; a thinning process and a scribing process are beneficially integrated; the production efficiency is improved; and the production cost is reduced.

The invention relates to a device for measuring time-domain waveforms of ultrafast pulses. The device comprises a microwave signal source, a femtosecond pulse laser, a light guide probe, a coaxial-to-coplanar converter, a coplanar waveguide and a lock-in amplifier, wherein the microwave signal source provides a microwave signal source for an ultrafast pulse generator and the femtosecond pulse laser, so that the ultrafast pulse generator generates the ultrafast pulses; the coaxial-to-coplanar converter transmits the received ultrafast pulses to the coplanar waveguide to generate ultrafast pulse electric fields; and time-delay lasers stimulate the light guide probe to generate photosensitive currents under the effect of the ultrafast pulse electric fields, and sampling is conducted through the lock-in amplifier. The device has the advantages that the ultrafast pulses with the pulse width of sub-10ps can be measured, the ultrafast pulses transmitted coaxially can be measured, and the ultrafast pulses transmitted in a planar manner can also be measured, so that a new breakthrough in measurement of the time-domain waveforms of the ultrafast pulses is realized, and the level of measurement of instruments, equipment and devices, which can generate the ultrafast pulses, is raised.

The invention provides an intrinsic optical fiber Fabry-Perot temperature sensor manufactured by a femtosecond pulse laser and a manufacturing method of the temperature sensor. The intrinsic optical fiber Fabry-Perot temperature sensor manufactured by the femtosecond pulse laser comprises an optical fiber, wherein a first optical fiber inner reflector and a second optical fiber inner reflector are arranged in the optical fiber; the first optical fiber inner reflector and the second optical fiber inner reflector are formed by changing a refractive index at a fiber core along the radial direction of a single-mode optical fiber core through the femtosecond pulse laser respectively; and the distance between the first optical fiber inner reflector and the second optical fiber inner reflector is 50 to 5,000mu m. The sensor has the characteristics of severe environment resistance, high stability and low loss, is easy to multiplex with an optical fiber communication network, has a simple optical path and is easy to implement, an optical fiber to be processed is not needed to be doped or sensitized, and a formed optical fiber Fabry-Perot structure is permanent and is difficult to disappear.

The invention provides a pulse polarizing and shaping-based two-color field chevilled silk-induced terahertz field enhancement system, which comprises a femtosecond pulse laser module, a laser pulse frequency doubling and beam splitting module, a pulse polarizing and shaping module, a pulse synchronization module, a terahertz radiation generation module and a terahertz detection module. Compared with a traditional femtosecond chevilled silk-induced terahertz wave generation method, the pulse polarizing and shaping-based two-color field chevilled silk-induced terahertz field enhancement system has the advantages that the system has a terahertz strength enhancement effect, the terahertz frequency spectrum can be effectively modulated and the system has potential value in applications of terahertz time-domain spectroscopy, terahertz imaging and atmosphere remote sensing.

The invention relates to wavelength measurement techniques, in particular to a precision laser wavelength measurement device and a precision laser wavelength measurement method. The precision laser wavelength measurement device comprises a femtosecond pulse laser, a PPLN (periodically poled lithium niobate) crystal, photonic crystal fibers, a first convex lens, a first attenuator, a first half-wave plate, a diaphragm, a second attenuator, a second half-wave plate, a first polarization beam splitter, a third half-wave plate and a second polarization beam splitter. The PPLN crystal, the photonic crystal fibers, the first convex lens, the first attenuator and the first half-wave plate are sequentially positioned on an emergent light path of the femtosecond pulse laser; the diaphragm, the second attenuator, the second half-wave plate, the first polarization beam splitter, the third half-wave plate and the second polarization beam splitter are sequentially positioned on a to-be-measured laser path. An emergent light path of the second polarization beam splitter is provided with a reflection grating, and a second convex lens, an optical filter, a third convex lens, a third attenuator and an avalanche diode detector are sequentially arranged on a reflection light path of the reflection grating; a spectrometer is connected to a signal output end of the avalanche diode detector. The precision laser wavelength measurement device and the precision laser wavelength measurement method have the advantages of simple structure, simplicity and convenience in operation, easiness in adjustment, low external disturbance, high stability and extremely high precision.

The invention discloses an improved system and an improved method for detecting the composition of a material by LIBS (Laser Induced Breakdown Spectroscopy) with high signal and noise ratio and low detection limit. The improved system combines femtosecond pre-ablation double-pulse LIBS and polarized resolution LIBS and comprises a femtosecond-pulse laser with a fixed wavelength, a super-continuum spectrum femtosecond-pulse laser, a light filter, a reflecting mirror placed by 45 degrees, a beam combining mirror, a beam expanding mirror, a telescope, a beam splitting mirror placed by 45 degrees, a polarization mirror with an adjustable polarization angle, an optical-fiber coupling mirror, an optical-fiber interface, an ICCD (Intensified Charge Coupled Device) spectrograph and a computer. The system disclosed by the invention has the advantages that double pulses are used for exciting the LIBS and light signals received are transmitted into the spectrograph by the polarization mirror, so that the detection limit of elements can be effectively reduced, the signal and noise ratio can be increased, the accuracy and the stability of detection can be improved, molecular spectrum and the atomic spectrum also can be detected simultaneously and more accurate information of the composition of the material can be provided.

The invention provides a femtosecond optical Kerr gate gated imaging device and method based on directional filtering. Light paths of the imaging device are divided into a detecting light path and a pumping light path. An object to be measured, a first convex lens, an optical Kerr gate composed of a polarizer, optical Kerr mediums and an analyzer, a second convex lens and a CCD are sequentially arranged on the detecting light path. The requirements of a 4f system are met. An optics delay line, a half wave plate and a space shaping device are sequentially arranged on the pumping light path. The imaging method includes the steps that femtosecond pulse lasers are changed into two beams through a beam splitter, and femtosecond detection pulse light passes the object to be detected and then is focused and enters the optical Kerr mediums in an incident mode; after femtosecond pumping pulse light opens the optical Kerr gate, components of information, carried in the femtosecond detection pulse light, of the object to be detected are instantly gated, finally, the components of the information reach the CCD, and a high-contrast-ratio image of the object to be detected is obtained. The femtosecond optical Kerr gate gated imaging device and method based on directional filtering have the advantages that cost is low, the light paths are simple and convenient to adjust, and optical Kerr gate gating and recognition of a characteristic structure of the object to be detected can be achieved at the same time.

Disclosed herein is a prompt gamma-ray detection apparatus for analyzing chemical materials using femtosecond pulse laser-induced neutrons, which can be effectively used in the nondestructive inspection of various materials, such as metals, coal, cement, radioactive materials and the like as well as explosives and chemical materials, and which can provide better measurement results for the analysis of basic materials, and a method of measuring prompt gamma-rays using the apparatus. The prompt gamma-ray detection apparatus is advantageous because it can non-destructively analyze the elements in a chemical sample using a femtosecond pulse laser-induced neutron generator that solves the problems of an atomic reactor for research or a radioactive isotope as a neutron radiation source.

The invention discloses a laser-assisted heating femtosecond pulse laser drilling device and method. The device includes a femtosecond pulse laser, a first beam expander, a CCD camera, a reflective plane mirror, a beam splitter, a convex lens, and a second beam expander. , a continuous laser, a femtosecond pulse laser controller, a continuous laser controller, a workpiece, a fixture, a movable workbench, a workbench controller, and a computer; meanwhile, a laser-assisted heating femtosecond pulse drilling method using the above-mentioned device is provided , the main principle is that before the femtosecond pulse laser processes the workpiece, the continuous laser is used to preheat the workpiece to be processed, and the phase change of the material does not occur during the preheating process, so as to ensure the processing advantages of the femtosecond laser and improve the quality of the material. The absorption rate of femtosecond pulse laser reduces the ablation threshold of femtosecond laser processing materials and improves the drilling efficiency of femtosecond pulse laser.

The invention discloses a method of manufacturing a surface cross-scale functional micro-nano structure; the method comprises the steps of first, scanning the surface of a base by millisecond pulsed laser to obtain a micro structural graph; scanning the manufactured micro structural graph by femtosecond pulsed laser to obtain manufacture a nano structural graph on the surface of the micro structural graph by induction. By using the method of manufacturing surface micro-nano functional structure combining millisecond pulsed laser etching and femtosecond laser induction, the cross-scale high-performance low-cost manufacture of the micro and nano functional microstructure can be achieved, the manufacturing efficiency is far higher than that of semiconductor process, and the method has a better application prospect.