169 results about "Broadband laser" patented technology

A broadband light source with a sufficiently long coherence length is impinged on the optical cavity. The broadband laser light reflects from the first and second surfaces of the cavity. The two light beams, either reflected or transmitted, are phase shifted from one another by an amount proportional to the optical path length of the cavity and inversely proportional to the wavelength of the light (4πnd/λ) The two light beams interfere with each other and form a modulated light beam that has a spectrum approximately like the laser's broadband spectrum multiplied by a cosine with a frequency 4πnd/λ. The modulated light beam is coupled to a spectrometer that measures the intensity of the light as a function of wavelength over a range of wavelengths. The Fourier transform of the spectrum contains a peak that is related to the OPL and is located at 2*n*d where n*d is the OPL.

Determination of steam quality by passing one or more laser beams through steam in a steam chamber and directly determining a total number of vapor molecules and a total number of water molecules based on absorption of radiation in the one or more laser beams by the water vapor phase and the liquid water phase in the steam. Specific volumes of water vapor phase and liquid water phase in the steam using the total numbers of water vapor and liquid water molecules are determined and the quality of the steam is calculated based on the specific volumes of the water vapor phase and the liquid water phase in steam. One embodiment comprises a narrow linewidth laser for measuring steam quality and another embodiment comprises multiple broadband lasers for measuring steam quality.

The invention discloses a dual-chirp optical parameter amplification method and device for broadband laser pumping. An initial laser source generates narrow-band laser which is divided into two beams, wherein the beam with the high energy is adopted as narrow-band pumping light, and broadband chirp pumping light is obtained after a spectrum widening device, and the light is emitted into a nonlinear crystal through a dichroic mirror; the beam with the low energy enters a super-continuum white light generator and a chirp mirror pair to obtain broadband chirp seed light, is emitted into the non-linear crystal through the dichroic mirror, and is coupled with the broadband chirp pumping light to be subjected to optical parameter amplification; finally, periodic magnitude pulse width femtosecond idler frequency light is obtained through a beam splitter and a pulse compressor. The spectrum widening broadband chirp pumping light is adopted, and the more frequency components are obtained; the broadband chirp pumping light and broadband chirp seed light dual-chirp scheme is adopted, and the instantaneous frequency correspondences are opposite, so that the spectral brand width of output idler frequency light is increased, and the femtosecond idler frequency light output of the periodic magnitude pulse width is achieved.

The invention relates to an adjustable laser coaxial powder-feeding nozzle suitable for round-spot laser fluxing and broadband laser fluxing, belonging to the technical field of laser processing. The nozzle has a water-cooling and guiding gas protection structures, is integrally in a hollow conical structure and comprises an upper body and a lower body which are sequentially connected and fixed by a thread. The adjustable laser coaxial powder-feeding nozzle is structurally characterized by being formed by respectively connecting a connecting tube with scale with a laser and a powder-feeding tube, a mechanism capable of vertically adjusting is formed by utilizing the thread, and the powder focus position is accurately adjusted; the lower body comprises one group of three coaxially distributed cones with round outlets and one group of three coaxially distributed cones with rectangular outlets to adjust different facula shapes, different types of faculae are mounted at the lower parts of corresponding outlets, an included angle between a powder channel and the nozzle axis ranges from 40 degrees to 50 degrees, and an included angle between a cooling water channel and the nozzle axis ranges from 30 degrees to 45 degrees.

An image projector having one or more broadband lasers designed to reduce the appearance of speckle in the projected image via wavelength diversification. In one embodiment, a broadband laser has an active optical element and a nonlinear optical element, both located inside a laser cavity. The broadband laser generates an output spectrum characterized by a spectral spread of about 10 nm and having a plurality of spectral lines corresponding to different spatial modes of the cavity. Different individual spectral lines effectively produce independent speckle configurations, which become intensity-superimposed in the projected image, thereby causing a corresponding speckle-contrast reduction.

The invention discloses a multi-sensor synergistic monitoring apparatus and method for broadband laser cladding. The apparatus comprises a displacement sensing unit, an image sensing unit and an information processing unit; a coaxial powder feeding head is provided with four sensor connection arms in central symmetry, and the end part of each sensor connection arm is respectively provided with the image sensing unit or the displacement sensing unit; and the two image sensing units are distributed around the coaxial powder feeding head at a given adjustable angle and used for acquiring an appearance image of two baths in different directions in the broadband laser cladding process. The information processing unit is used for melting and processing height data acquired by the displacement sensing unit and the bath images acquired by the image sensing unit, calculating and displaying an area as well as a three-dimensional size, height of a forming layer, a defocusing amount and a lap joint rate of a broadband rectangular bath in real time. By adopting the multi-sensor synergistic monitoring apparatus and method, the broadband laser cladding process can be precisely and comprehensively monitored in real time.

The invention relates to a laser broadband fusion covering device, and belongs to the field of 3D (three dimensional) formation. A laser beam sent by a laser can be converted and projected on a processing surface for broadband laser fusion covering processing by the laser broadband fusion covering device; the laser broadband fusion covering device comprises a reflecting mirror and a dual-molded- surface reflecting component; the laser beam is reflected to the dual-molded-surface reflecting component by the reflecting mirror; the dual-molded-surface reflecting component comprises an upper reflecting surface and a lower reflecting surface positioned under the upper reflecting surface; the upper reflecting surface is a parabolic focusing molded surface; the lower reflecting surface is a plane; after the upper reflecting surface receives the laser beam, the laser beam is reflected, so that a broadband focusing line spot is formed on the processing surface; after the lower reflecting surface receives the laser beam, the laser beam is reflected, so that a rectangular light spot is formed on the processing surface; the rectangular light spot is positioned at the outer side of the broadband focusing line spot. The laser broadband fusion covering device has the advantages that the technology heat treatment requirements of different materials and structures can be met; the defect probability of fusion layer residual thermal stress, cracks and the like is reduced.

The invention relates to a coaxial powder feeding device for broadband laser cladding and a powder feeding method thereof. The device comprises a sleeve module; a light beam isolation cover, and an inner-layer air cover, an outer-layer air cover and a cooling water cover for coating the light beam isolation cover in sequence from inside to outside are arranged at the bottom end of the sleeve module; two powder feeding pipes symmetrically arranged about the light beam isolation cover are arranged between the inner-layer air cover and the outer-layer air cover at the bottom end of the sleeve module; outlets of the powder feeding pipes are rectangular pipes; outlets of the light beam isolation cover, the inner-layer air cover, the outer-layer air cover and the cooling water cover at the bottoms are rectangular; and the sleeve module is provided with a water injecting port, a water outlet, an outer-layer protective gas inlet, an inner-layer protective gas inlet and a powder feeding inlet. The method comprises three steps of connection of external source equipment, powder feeding device parameter adjustment and coaxial broadband powder feeding laser cladding. The device can prevent fused metal liquid from splashing to block the outlet of the powder feeding device, can enable the powder spot pavement to become more uniform in powder spot shaping, and is simple in structure and easy to machine.

The invention discloses a chirped pulse velocity interferometer. In the chirped pulse velocity interferometer, broadband laser pulses output by a broadband pulse laser light source are changed into linear polarization linear chirped pulses after passing through a polarizer and a pulse stretcher; polarization light S and polarization light P which are perpendicular in polarization direction are produced after the linear chirped pulses pass through a polarization splitting prism, and then the polarization light S and the polarization light P are successively emitted into the surface of a tested sample; the beat-wave interferometry is conducted on reflected light at a certain included angle, and produced beat-wave interferometric fringes are recorded through an imaging type spectrometer. A certain delay time difference exists before the polarization light S and the polarization light P are emitted into the surface of the sample, and synchronous transmission is achieved through optical path compensation after the polarization light S and the polarization light P are reflected by the surface of the sample. The oscillation penetrating direction of the polarizer is perpendicular to that of an analyzer. By means of the chirped pulse velocity interferometer, the time distinguishing of sub-picosecond scale can be achieved, the imaging type spectrometer serves as the corresponding recording system, an expensive streak camera recording system is avoided, and therefore the cost of a test system is effectively controlled.

The present invention relates to a 3-color multiplex CARS spectrometer. In the 3-color multiplex CARS spectrometer, Raman resonance is achieved for multiple molecular vibrations of a sample by the combination of a short-wavelength pump beam generated by a broadband laser light source and a long-wavelength Stokes beam generated by a stable laser light source, and another short-wavelength laser beam having a narrow linewidth is then introduced separately to serve as a probe beam that interacts with the laser-driven sample, thereby generating CARS spectral signals whose wavelength components can be resolved. Accordingly, the 3-color multiplex CARS spectrometer solves problem of the conventional 2-color multiplex CARS spectroscopy in which the wavelength decomposition of CARS signals, necessary for high spectral resolution, is not possible with broadband pump light causing the CARS spectrum distortion.

The invention discloses a dynamic strain measurement method based on Brillouin phase shift detection. The dynamic strain measurement method comprises the following steps of dividing laser signals into two paths; after one path of signals are subjected to broadband frequency shift, generating optical heterodyne to detect local oscillator light wave and detection signal light wave, and synchronously injecting the local oscillator light wave and the detection signal light wave into a sensor fiber; after spectrum broadening, causing the other path of laser signals and a pulse generator to generate broadband Brillouin pulse pumping light wave, and injecting the broadband Brillouin pulse pumping light wave into the sensor fiber; setting a modulator to drive a voltage waveform to introduce linear chrip so as to obtain broadband laser, which is approximate to a rectangular spectrum, and extending a linear region with the Brillouin phase shift of the sensor fiber; carrying out coherent detection on the local oscillator light wave and the detection signal light wave through coherent demodulation of a beat frequency signal and a radio frequency signal which are generated by photovoltaic conversion so as to obtain the Brillouin phase shift of the detection signal light wave; demodulating information of a strain signal of the sensor fiber. The dynamic strain measurement method has the advantages that the signal to noise ratio is improved, the dynamic strain measurement range is increased and the detection speed is improved. The invention further discloses a dynamic strain measurement device based on the Brillouin phase shift detection.

The invention discloses a method for preparing a hydroxy apatite biological ceramic coating containing fluorine. The method comprises the steps of evenly mixing 2.3% of calcium fluoride powder by weight and 97.7% of hydroxyapatite powder by weight, utilizing polyving akohol solution with concentration of 2% to serve as binder to allocate the mixed powder, presetting the allocated mixed powder on a titanium alloy base plate, and utilizing a carbon dioxide laser to perform broadband laser cladding on the titanium alloy base plate to generate the hydroxy apatite biological ceramic coating containing the fluorine, wherein the cladding process adopts two process parameters as follows: the laser output power P of the carbon dioxide laser ranges from 0.5kW to 1kW, the scanning speed V ranges from 150nm/min to 250nm/min, the rectangular spot dimension D is 15mm*2mm, and argon shield is adopted. By means of the method, good biological activity of the ceramic coating and high strength and good toughness of metal are combined together, and the hydroxy apatite coating containing the fluorine can protect the titanium alloy base plate from being corroded by the human physiological environment. Besides, the coating and the metal of the base plate are combined through the laser cladding preparation technique, so that the hydroxy apatite biological ceramic coating containing the fluorine meets mechanical performance requirements of implant materials.

The invention provides an ultra-long distance distributed optical sensing device based on two-way optical amplification. The device comprises a controlling and processing device, a broadband laser device (1) and a first optical fiber coupler (2), parallel first optical fiber arm (3) and second optical fiber arm (4), a second optical fiber coupler (6), a sensing link (7) and a faraday rotation mirror (8), all of which are orderly connected together; a photoelectric detector (20) is further connected between the controlling and processing device and the first optical fiber coupler (2). The ultra-long distance distributed optical sensing device is long in sensing distance, relatively high in accuracy and good in positioning effect.

The invention discloses a Michelson interferometric optical-fiber hydrogen sensor based on a PM-PCF. The Michelson interferometric optical-fiber hydrogen sensor is composed of a broadband laser source, a polarization controller, a first transmission optical fiber, a 3-dB coupler, a second transmission optical fiber, the PM-PCF plated with a Pd/Ag thin film, a third transmission optical fiber, a fourth transmission optical fiber, a spectrograph and a constant-temperature air chamber. Lasers emitted by the broadband laser source pass through the polarization controller, and a linearly-polarized laser beam is obtained and divided by the 3-dB coupler into two same laser beams which enter the PM-PCF plated with the Pd/Ag thin film and the third transmitting optical fiber respectively. As the Pd/Ag thin film absorbs hydrogen, swells and presses an air hole in the PM-PCF, the phase of a transmission mode in a film plating area is changed, and the two laser beams are reflected through the end faces and then gathered at the transmitting end of the 3-dB coupler; as the constant phase difference exists and interference occurs, an interference spectrum is received by the spectrograph. As the corresponding relationship exists between the drifting amount of the interference spectrum and the concentration of the hydrogen, the concentration of the hydrogen is accurately measured. The Michelson interferometric optical-fiber hydrogen sensor is simple in structure, high in sensitivity and small in temperature drifting. A feasible scheme is provided for online monitoring of the concentration of the hydrogen.

The invention relates to a tunable laser for outputting non-polarized light. The tunable laser is mainly and technically characterized by comprising a first reflection mirror, a broadband laser gain medium, a tunable Fabry-Perot filter, a tunable acousto-optic filter, a second reflection mirror, a third reflection mirror and a laser control circuit, wherein a broadband light beam sent from the broadband laser gain medium can be filtered by the tunable Fabry-Perot filter and then is filtered by the tunable acousto-optic filter; a first-grade diffraction light beam is divided into two beams of polarized light with vertical polarized states; and a zero-grade diffraction light beam of the tunable acousto-optic filter is taken as an output light beam of the laser device. According to the tunable laser disclosed by the invention, continuous, the continuous, rapid and precise tuning can be performed on the output light of the laser in a wide spectral range; and the tunable laser has the characteristics of absence of mechanical movement parts, high electronic tuning speed, stable and reliable performance, small size, easiness in production and the like, and can be widely applied to the fields of lasers, optical tests, optical fiber communication, biological and medical instruments, optical fiber sensor networks and the like.

The invention relates to a parametric amplification or parametric conversion system of an adjustable broadband laser pulse of a spectral response curve, which belongs to the field of nonlinear intense laser. The parametric amplification or parametric conversion system comprises a spatial frequency chirp transformation device, a splitting, attenuation and optical delay device, a partially reflecting mirror, a focusing cylindrical lens, a fan-shaped periodically poled crystal, a filtering device and a collimating cylindrical lens, wherein the partially reflecting mirror, the focusing cylindrical lens, the fan-shaped periodically poled crystal, the filtering device and the collimating cylindrical lens are arranged on an optical axial line in sequence, the output pump pulse of the splitting, attenuation and optical delay device enters the partially reflecting mirror from a 45-degree angle, and the installation directions of the partially reflecting mirror and the filtering device respectively form a 45-degree included angle with the output optical shaft of the spatial frequency chirp transformation device. The system of the invention not only can realize the parametric amplification or conversion for almost identical gains of all frequency components within the input signal bandwidth, but also can adjust the intensity and the position of each pump pulse according to needs, so as to change the bandwidth or the spectral property of the frequency response curve or the output pulse bandwidth. Moreover, the system has the advantages of simple structure, convenient calibration, flexible crystal selection and the like.

The present invention provides a parallel distributed computing-based multi-channel optical fiber grating vibration signal intelligent sensor system. The system includes a strain measurement Bragg grating, a semiconductor laser which is used for providing broadband laser to the Bragg grating, an optocoupler which is connected with the semiconductor laser and the Bragg grating, a beam splitting system which is connected with the optocoupler, receives Bragg reflected spectral signals and completes the spatial spreading and focusing of the spectral signals, a line-array image detector which is connected with the beam splitting system, carries out light intensity detection on the spectral signals of each pixel position in a high-speed scanning manner and outputs corresponding optoelectronic signals in a serial manner, a signal conditioning amplification and analog-to-digital conversion circuit which is connected with the line-array detector, an FPGA-based embedded demodulator which is connected with the signal conditioning amplification and analog-to-digital conversion circuit, realizes the fitting and interpolation operation of an spectral curve to obtain the peak coordinates of the spectral signals, and a bus interface module which provides a variety of kinds of digital buses.

A laser amplifier includes a broadband laser gain medium having a first lateral face spaced from an opposing second lateral face at a wedge angle with respect to the first lateral face. At least the first lateral face receives a pump beam and one of the first and second lateral faces receives a seed beam. A first coating on the first lateral face is highly transmissive at the pump beam wavelength. A second coating is disposed on the second lateral face. In one example, the first coating is highly reflective at the seed beam wavelength over a first wavelength band and the second coating is highly reflective at the seed beam wavelength over a second wavelength band (partially or fully) overlapping the first wavelength band.

The invention relates to a broadband laser cladding molten pool contour curve and a modeling method thereof. The molten pool contour curve equation is as follows: (y-Wm/2)/2*W0=+/-(x/Lm)*(1-x/Lm)<j>, 0<=x<=Lm. An XOY coordinate system is a Descartes coordinate system built with the center point of the front edge of the molten pool as the origin O and the cladding scanning direction as the negative direction of the x axis. In the equation, y is the longitudinal coordinate of the molten pool profile curve in the XOY coordinate system, x is the horizontal coordinate, Wm is the center width ofthe molten pool, W0 is the edge width of the molten pool, and Lm is the total length of the molten pool in the cladding direction. The curve is obtained by summarizing the molten pool shape detectionresult of broadband laser cladding process test. The modeling method of the molten pool contour curve is highly accurate. The shape information of the molten pool is described with simple and effective geometric parameters of the molten pool. A theoretical basis and a data reference are provided for broadband laser cladding process monitoring and cladding layer quality control.