86 results about "Mid infrared laser" patented technology

The invention relates to the technical field of laser processing, and discloses a laser processing device and method suitable for TGV forming, and the method comprises the steps: S1, a glass substrate is scanned in a confocal manner, a three-dimensional topological graph is obtained, and the three-dimensional topological graph comprises the three-dimensional coordinate, the thickness gradient and the positioning mark of the glass substrate; s2, based on the three-dimensional topological graph, a through hole body is formed through ultraviolet femtosecond laser etching, and intermediate infrared laser is synchronously and dynamically controlled to etch the side wall of the through hole body to generate a taper through hole with a preset taper angle; and S3, the incident angle of the ultraviolet femtosecond laser is adjusted on the side wall of the taper through hole according to the three-dimensional topological graph, and a plurality of heat dissipation grooves are etched through the ultraviolet femtosecond laser. According to the laser processing device and method suitable for TGV forming, signal integrity optimization and active heat dissipation functions are achieved in the same through hole, the application range of the TGV is widened, and the stability of the TGV during use is improved.

The invention discloses a high-power intermediate infrared fiber laser. The fiber laser is composed of a first pumping source, a second pumping source, a pumping beam combiner, a high-reflectivity fiber grating, a low erbium-doped fluoride fiber, a low-reflectivity fiber grating, a cladding light filter, a fiber end cap, a collimating lens and a dichroscope. The mode of combining erbium ion ground state transition achieved through fiber core pumping and erbium ion excited state transition achieved through cladding pumping is adopted, mid-infrared laser upper energy level particle number accumulation is obtained, and meanwhile laser lower energy level particles are effectively consumed through the cladding pumping transition process. And the population inversion state of the laser system is kept, and the particle circulation rate and the quantum efficiency from the pump light to the intermediate infrared laser are improved, so that the generation of high-power and high-efficiency intermediate infrared fiber laser is realized.

The invention provides a high-speed large-capacity intermediate infrared laser communication method and system based on an integrated waveguide, and is mainly used for solving the problems that when an existing space laser communication system adopts intermediate infrared band transmission, a frequency conversion scheme based on a block material is poor in phase matching, large in size, low in conversion efficiency, low in cost and the like. And the actual requirements of high-speed and large-capacity communication are difficult to meet. According to the high-speed large-capacity mid-infrared laser communication method based on the integrated waveguide, the first integrated waveguide is adopted to realize conversion from a near-infrared band to a mid-infrared band frequency comb, the wavelength division multiplexing technology is combined to maximize the channel capacity, and then the second integrated waveguide is adopted to restore a near-infrared band optical signal. The problems of insufficient capacity, generation of attenuation and loss, low rate and the like when near-infrared band optical signals are transmitted in an atmospheric channel are avoided, space laser communication with the rate of Tbps magnitude is realized, an optical field can be restrained in a micro-nano waveguide structure to the greatest extent, and the frequency conversion efficiency is improved.

A first pumping source and a second pumping source are combined through a pumping beam combiner and are coupled into an erbium-doped fluoride fiber and a high-reflectivity fiber bragg grating, and the erbium-doped fluoride fiber and a low-reflectivity fiber bragg grating form a laser resonant cavity. The intermediate infrared laser is output through the low-reflectivity fiber bragg grating, the cladding light filter and the optical fiber end cap; the high-reflectivity fiber bragg grating and the low-reflectivity fiber bragg grating have the same grating period, the fourth-order harmonic reflection wavelength of the grating is located in the emission spectrum range of transition of erbium ions from the 4F9 / 2 energy level to the 4I9 / 2 energy level, and the fifth-order harmonic reflection wavelength of the grating is located in the emission spectrum range of transition of erbium ions from the 4I11 / 2 energy level to the 4I13 / 2 energy level; by adjusting the power of the first pumping source and the second pumping source, the net gain of laser transitions from the 4F9 / 2 energy level to the 4I9 / 2 energy level and transitions from the 4I11 / 2 energy level to the 4I13 / 2 energy level is regulated and controlled, and switching of laser working wavelengths is achieved.

The invention provides an efficient OPO system with a bicrystal compensation and independent pumping regulation and control structure, and relates to the technical field of laser nonlinear frequency conversion. The device comprises a pump laser, a light source regulation and control unit, an incidence adjustment unit, an OPO resonant cavity and an output separation unit which are sequentially arranged, the OPO resonant cavity comprises a walk-off compensation and frequency conversion module and a tuning module, and the walk-off compensation and frequency conversion module comprises a nonlinear crystal I and a nonlinear crystal II which have opposite cutting angles. And a tuning module is arranged between the nonlinear crystal I and the nonlinear crystal II. The OPO system based on the bicrystal structure has space walk-off angle compensation and pump light independent regulation and control capabilities, and is suitable for constructing near-infrared and intermediate-infrared laser sources with high efficiency and high stability. According to the invention, the optical path structure is flexible, the multi-crystal and multi-band adaptation is supported, and the system compatibility is good; miniaturization and intelligent integration are easy, and industrial application and popularization are facilitated.

The invention discloses a dynamic early warning method for a high-sulfur-content natural gas leakage influence range in the field of leakage gas monitoring. The method comprises the following steps: arranging an intermediate infrared laser remote measurement system in a high-sulfur-content natural gas field to monitor the concentration of hydrogen sulfide gas in the gas field in real time; judging whether the gas field is leaked or not according to the concentration of the hydrogen sulfide gas, if so, executing the next step, otherwise, repeating the judgment; calculating leakage flow and leakage hole radius; and substituting the leakage hole radius and the leakage flow into the optimized time sequence Gaussian smoke cloud model to obtain the concentration values of the hydrogen sulfide gas at different moments and different spatial positions, namely the influence ranges of the leakage gas at different moments. According to the method, the size of the leakage hole can be calculated, the dynamic correction process of the three-dimensional leakage range of the Gaussian model is completed, various conditions of mixed gas leakage factors are considered at the same time, and the dynamic calculation process of the influence range of the leakage gas is achieved.

The invention discloses a microphone device and method capable of locating a sound source and a digital human device.The device comprises a plurality of basic units and a signal processing module, and each basic unit is composed of pickup microphones annularly and evenly arranged at intervals and an infrared laser distance measuring sensor located in the center; the plurality of basic units are arranged to form a ranging microphone array matrix. The signal processing module synchronously collects a sound signal of the pickup microphone and a distance signal of the infrared laser distance measuring sensor, and firstly processes the sound signal based on a TDOA algorithm to obtain a two-dimensional plane coordinate of a sound source; and positioning a corresponding basic unit according to the two-dimensional plane coordinate, calling a distance signal of an infrared laser distance measuring sensor in the unit, calculating a vertical distance between the sound source and the array matrix in combination with the two-dimensional coordinate, and finally determining a three-dimensional coordinate of the sound source. According to the invention, high-precision sound source three-dimensional positioning is realized.

The invention discloses a fuel gas leakage detection system based on mid-infrared laser, relates to the technical field of fuel gas detection, and aims to solve the problems that a large-area region is difficult to cover quickly and only close-range detection can be carried out in an existing laser fuel gas leakage detection method. The gas leakage detection system comprises a laser emission module, an infrared imaging detector module and a data processing module, the laser emission module is used for emitting an intermediate infrared laser beam to a to-be-detected area; the infrared imaging detector module is used for collecting an infrared spectrum signal of the to-be-detected area in real time; the infrared spectrum transmitting module is used for transmitting the infrared spectrum signal to the data processing module; and the data processing module is used for processing the received infrared spectrum signal to obtain a gas leakage detection result of the to-be-detected area. The method is suitable for detecting gas leakage in a natural gas pipeline and a liquefied petroleum gas storage tank area.

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.

The invention provides a mid-infrared optical frequency comb. The mid-infrared optical frequency comb comprises a near-infrared optical frequency comb seed source of a polarization-maintaining all-fiber structure; the all-fiber nonlinear amplification and pulse compression module is connected with the near-infrared optical frequency comb seed source through a polarization maintaining fiber and is used for amplifying the power of the seed light and compressing the pulse width after generating a linear chirped pulse; the all-fiber nonlinear spectrum broadening module is connected with the all-fiber nonlinear amplification and pulse compression module through a polarization maintaining fiber and is used for broadening a laser spectrum; the difference frequency module is used for receiving the laser pulse processed by the all-fiber nonlinear spectrum broadening module and generating an intermediate infrared laser pulse through intra-pulse self-difference frequency; wherein the seed source, the all-fiber nonlinear amplification and pulse compression module and the all-fiber nonlinear spectrum broadening module are connected through a polarization maintaining fiber to form an all-fiber integrated structure. By adopting the scheme, the anti-interference capability of the system can be enhanced, miniaturization and high operation reliability are realized, the debugging process is simplified, and the difference frequency efficiency is improved.

The mid-infrared optical parametric oscillator pumped by the dual-wavelength nanosecond pulse solid laser can simultaneously output 1.9 micron laser and 2.1 micron laser, realizes broad spectrum / multi-wavelength output of the mid-infrared optical parametric oscillator, and can ensure that mid-infrared laser has excellent beam quality and relatively high output power. The output power of the 1.9 [mu] m optical fiber laser pumping source is hectowatt magnitude, and the 1.9 [mu] m optical fiber laser pumping source serves as a pumping source of a Ho crystal in the solid laser oscillator. In a Tm solid laser oscillator and a Ho solid laser oscillator, a resonant cavity comprises two plano-concave sub-cavities, the two plano-concave sub-cavities are a Tm crystal oscillation cavity and a Ho crystal oscillation cavity respectively, the two plano-concave sub-cavities share one output mirror, the Tm crystal oscillation cavity adopts a 793 nm semiconductor laser for pumping, and the Ho crystal oscillation cavity adopts a 1.9 [mu] m optical fiber laser pumping source I for pumping; in the phosphorus-germanium-zinc optical parametric oscillator, a planar four-mirror annular cavity is used as a single-resonance optical parametric oscillation cavity.

The application provides a high-sensitivity multi-gas real-time monitoring device and method, which comprises a controller, wherein the controller is connected with a main control circuit; the main control circuit is connected with an indicating laser and a mid-infrared laser array; the indicating laser and the mid-infrared laser array are connected with a multi-pass gas cell through a fiber coupling structure; a photoelectric detector is arranged on the light outlet side of the multi-pass gas cell; and the photoelectric detector is connected with the main control circuit; the controller generates modulation signals with different frequencies to modulate the mid-infrared laser array; the indicating laser emitted by the indicating laser and the mid-infrared laser emitted by the mid-infrared laser array are coupled into a coaxial light beam through the fiber coupling structure and enter the multi-pass gas cell; the photoelectric detector collects signals with target gas information passing through the multi-pass gas cell and simultaneously analyzes the concentrations of multiple target gases through a signal conditioning algorithm. The application has the characteristics of high sensitivity, low detection limit, real-time monitoring, convenient installation, strong anti-interference ability, maintenance-free and wide application range.

The application relates to the field of laser technology, in particular to a device and a method for generating wide-tuning narrow-line-width mid-infrared laser, wherein the pump light emitted by a nanosecond pulse OPO base frequency pump source is reflected to a beam splitter by a full reflection mirror after passing through a first adjuster; the pump light emitted by a continuous wave OPO base frequency pump source is irradiated to the beam splitter after passing through a second adjuster; the two beams of pump light are combined after passing through the beam splitter, are focused after passing through a plano-convex lens, are irradiated to a first plano-concave full reflection mirror, and then are transmitted to a nonlinear crystal to generate signal light and idler mid-infrared laser through nonlinear frequency conversion; the idler mid-infrared laser and the residual pump light are transmitted to a doublet mirror and are separated by the doublet mirror; the signal light is reflected to the nonlinear crystal in sequence through a second plano-concave full reflection mirror, a first plane full reflection mirror, a second plane full reflection mirror and the first plano-concave full reflection mirror, and an oscillation closed loop is formed. The application realizes that the pulse OPO outputs a pulse with a line width less than 90 MHz in the tuning range, and the extraction efficiency of the idler light is as high as 9.3%.

The invention belongs to the technical field of laser materials and preparation thereof, and particularly relates to a mid-infrared 2.9 mu m wave band enhanced fluoride laser crystal and a preparation method and application thereof, the chemical composition of the crystal is any one of xHo, yA, zB: Ae1F2 or xHo, yA, zB: Ae1Ae2F4, ho < 3 + > ions are used as active ions, A < 3 + > ions are used as deactivation ions of the Ho < 3 + > ions, and B < 3 + > ions are used as structure regulation ions; 0.5 < = x < = 1.5 at.%, 0.05 < = y < = 0.15 at.%, and 1 < = z < = 30 at.%; the crystal structure belongs to a cubic system, and the space group is Fm-3m (225). Compared with the prior art, the crystal can realize higher luminous intensity in a 2.9 mu m wave band, realizes reversion of fluorescence intensity relative to a 1.9 mu m wave band, has better crystal quality and higher-power intermediate infrared laser output capability, and has the advantages of high gain bandwidth, high gain section, high power, high slope efficiency and the like in an intermediate infrared wave band.

The application relates to a high-power mid-infrared optical parametric oscillation amplification device directly pumped by a Tm laser, and belongs to the technical field of high-power mid-infrared lasers. The device comprises a Tm:YLF seed laser, a Tm:YLF slab amplifier, a ZGP optical parametric oscillator and a ZGP optical parametric amplifier in sequence. The Tm:YLF seed laser outputs 1.908-micron fundamental light, the power of the 1.908-micron fundamental light is amplified through the Tm:YLF slab amplifier, and then the ZGP optical parametric oscillator and the ZGP optical parametric amplifier are directly pumped. The injection end and the output end of the Tm:YLF slab amplifier are both provided with a fundamental light coupling isolation system. A mid-infrared laser coupling isolation system is arranged between the ZGP optical parametric oscillator and the ZGP optical parametric amplifier. The ZGP optical parametric oscillator and the ZGP optical parametric amplifier are directly pumped by high-power Tm:YLF lasers, so that the power of the mid-infrared laser and the overall efficiency of the system are improved.

The invention provides a method for generating high-peak-power intermediate infrared ultrafast laser based on pulse / continuous wave system parametric conversion. Comprising a pumping source 1 which is used for providing mu J-level energy and 10ps-level pulse width near-infrared pulse laser. Pump light is focused and subjected to path adjustment through the high reflectors 2, 3 and 5 and the lens 4, the pump light and signal light are combined through the dichroscope 15, and optical parametric conversion is carried out through the nonlinear crystal 16. Comprising a signal source 6 which is used for providing near-infrared continuous waves, signal light power and polarization direction are accurately regulated and controlled through an erbium-doped optical fiber amplifier 7, an attenuator 8, a polarization maintaining optical fiber circulator 9, a collimator 10 and a half-wave plate 11, and focusing and path adjustment are carried out through a lens 12 and high reflectors 13 and 14. Comprising a dichroscope 17 and long-pass filters 18 and 19 and is used for filtering out mid-infrared laser.

The application provides a niobium phosphate nonlinear optical crystal and preparation and application thereof. 12 Nb3P7O 31 , belongs to an orthorhombic system, a space group is Pna21, is a non-central symmetric structure, cell parameters are: a=0.5 nm, b=1.0 nm, c=0.5 nm, and Z=4, has a large nonlinear optical effect (3xKDP), is phase-matched, a theoretical indirect band gap is 5.11 eV, has a large laser damage threshold, a wide transmission range, stable physical and chemical properties, good mechanical properties, is not easy to deliquesce, and is easy to preserve, and can be used as a ferroelectric crystal, a pyroelectric crystal or a laser substrate material, and is widely applied in preparation of middle infrared laser nonlinear optical composite functional devices, piezoelectric devices, laser frequency conversion devices and the like.

The invention relates to the field of chemical oxygen-iodine lasers, in particular to a mid-infrared wavelength conversion method and device of a chemical oxygen-iodine laser. Firstly, a pair of pulsed magnetic field generators is placed on the upper side and the lower side of a gain area of an original continuous wave chemical oxygen-iodine laser; the hydrogen Raman pool is used as a magnetic gain switch to enable the laser to output laser pulses with higher peak power, then 1315nm wavelength laser output by the oxygen-iodine chemical laser is guided into the hydrogen Raman pool, the original 1315nm wavelength laser is converted into 2900nm wavelength laser through Raman scattering to be output, finally, the 2900nm wavelength laser is guided into the vacuum bin containing the iron-doped zinc selenide crystal, and the iron-doped zinc selenide crystal is obtained. And by pumping the iron-doped zinc selenide crystal, the laser with the wavelength of 2900 nm is further converted into intermediate infrared laser pulses with the wavelength of 4000-5000 nm. On the premise that the original laser structure is not influenced, the oxygen-iodine chemical laser has the possibility of being applied to the middle infrared band.

This application provides a cavity-enhanced mid-infrared photothermal vibration measurement system and method, relating to the field of photothermal vibration spectrum detection of materials, aiming to improve the accuracy and sensitivity of detection. The measurement system includes a cavity-enhanced substrate, a mid-infrared laser, a laser vibrometer, and a lock-in amplifier. The cavity-enhanced substrate includes a substrate and an asymmetric Fabry-Perot resonator. The asymmetric Fabry-Perot resonator includes a reflective layer, an intermediate dielectric layer, and a layer to be tested, sequentially stacked on the substrate. The mid-infrared laser applies mid-infrared laser light to the layer to be tested, causing the layer to generate a photothermal vibration signal. The laser vibrometer detects the photothermal vibration signal and converts it into a detection electrical signal. The lock-in amplifier extracts the detection electrical signal to determine the photothermal vibration spectrum of the layer to be tested. The ratio of the thickness of the intermediate dielectric layer to the thickness of the layer to be tested ranges from 0.8 to 10. The refractive index of the material of the layer to be tested is less than the refractive index of the material of the intermediate dielectric layer, but greater than the refractive index of air.

The invention discloses an automatic calibration gas detection system and calibration method based on cooperation of mid-infrared light and visible light, and relates to the technical fields of optical detection, environmental monitoring, automatic control and the like, mid-infrared laser and visible laser are combined and emitted into a multiple reflection pool, and initial alignment is carried out based on visible laser of indicating light in an initial state; a high-reflectivity mirror bracket of the multiple reflection pool is provided with a stepping motor used for adjusting the angle of a high-reflectivity mirror, in the operation process, the signal intensity and the signal-to-noise ratio are monitored in real time, the stepping motor is driven to adjust the angle of the high-reflectivity mirror according to the monitoring result, and closed-loop automatic calibration is achieved. According to the invention, the invisible mid-infrared light path is visualized by using coaxial indicating light, so that the calibration time of initial installation and daily maintenance is shortened, the angle of the high-reflectivity mirror is automatically adjusted, the offset of the light path is compensated and the optimal detection state is kept during the operation of the system, and the long-term stability and reliability of the system are improved.

The application provides a 2.8 mu m single-frequency fiber laser based on a pump-enhanced saturable absorber and belongs to the technical field of mid-infrared laser. The linear resonant cavity of the laser is composed of a low-refractivity fiber grating and a high-refractivity fiber grating, and a first pump coupler, an erbium-doped fluoride gain fiber, a pump light stripper and a pump-enhanced saturable absorber filter device are sequentially arranged in the cavity. The filter device contains enhanced pump light injected by a second pump source through a second pump coupler and used for exciting the absorption characteristics of the erbium-doped saturable absorption fiber; the laser of the first pump source is used for pumping the gain fiber to generate laser oscillation, and the enhanced pump light is used for forming a MHz-level ultra-narrow band dynamic grating in the saturable absorption fiber. The dynamic grating and the static filter of the fiber grating work cooperatively to realize stable single-longitudinal-mode selection, and finally the single-frequency laser is output from the first fiber end cap. The application realizes compact structure and high stability of 2.8 mu m single-frequency laser output.

A narrow linewidth mid infrared laser, including a pumping laser diode with a fast-axis compressor and a pumping wavelength λo; and an optical resonator arranged to receive the pumping wavelength λo, the optical resonator including a laser crystal with a lasing wavelength λp, a dichroic mirror, and a nonlinear crystal to generate an idler wavelength λi.

The invention relates to a thulium-zirconium co-doped gadolinium scandate near-middle infrared band laser crystal and a preparation method and application thereof, the chemical composition of the crystal is represented as TmxZryGd1-xSc1-yO3, the value range of x is more than or equal to 0.001 and less than or equal to 0.05, the value range of y is more than or equal to 0.005 and less than or equal to 0.05, and the space group of the crystal is Pnma and an orthorhombic system. The preparation method of the thulium-zirconium co-doped gadolinium scandate near-middle infrared band laser crystal is an edge-defined film-fed crystal method. Compared with the prior art, the laser crystal provided by the invention can efficiently realize output of near-middle infrared band laser near 1.5 microns and 2.3 microns, and can be applied to the fields of laser medical treatment, environmental monitoring, realization of output of near-middle infrared laser as an optical parametric oscillation (OPO) pumping source and the like.

An atomic force microscope-based nanoscale photothermal ion in-situ characterization device, comprising: an atomic force microscope module comprising an AFM conductive probe in contact with a to-be-measured region of a to-be-measured sample; a nanometer infrared photothermal excitation module for emitting pulsed mid-infrared laser to the to-be-measured region to cause the micro-cantilever of the AFM conductive probe to deform; a photothermal ion signal detection module comprising a signal detection unit and a data processing and display unit in communication, the signal detection unit being used to acquire the micro-cantilever signal of the AFM conductive probe; wherein the data processing and display unit acquires the photothermal ion second-harmonic signal of the to-be-measured region based on the micro-cantilever signal of the AFM conductive probe to display the image of the ion transport micro-region surface distribution of the to-be-measured region.

This invention discloses a laser irradiation therapy device based on metal film directional scattering beam expansion, comprising a chassis, a power supply module, an intelligent control module, a mid-infrared laser emission module, and a human-computer interaction component mounted on the chassis. It also includes a laser transmission module, a metal film directional scattering beam expansion and homogenization module, a visible laser emission module, a temperature detection module, and an adjustable support. During operation, the mid-infrared laser is transmitted to the beam-combining module via a light guide arm or flexible mid-infrared hollow fiber, while the visible laser is transmitted to the beam-combining lens via a visible light incident channel. The two lasers form a coaxial composite beam at the beam-combining lens, which together irradiates the metal film component. After directional scattering and beam expansion, the beam is output from the light outlet to the working area, forming an expanded and homogenized light spot. This therapy device, with the metal film component as the core optical shaping component, has advantages such as clear structure, adjustable light output direction, adjustable light spot area, visualized working area, and high safety.

The invention discloses a hollow anti-resonance optical fiber with a large mode field area and ultralow loss in a middle infrared band. The cross section structure is composed of a central pentagonal hollow core area, a peripheral glass sheet connected coaxial semicircular nested pipe cladding and an outer cladding sleeve. The hollow core is an air channel with a pentagonal outline and is used for realizing the propagation of light in a low-loss medium; the cladding is composed of five symmetrically-distributed coaxial semicircular nested tube units, each unit comprises an inner semicircular arc glass sleeve and an outer semicircular arc glass sleeve which are connected by glass sheets to form a connected structure, and an anti-resonance boundary with a periodic microstructure is formed. According to the structure, the size of an air hole, the thickness of a glass wall, the radius ratio of two layers of semi-circular arcs and geometric symmetry are accurately regulated and controlled, and light of a specific wave band is limited in the hollow core through the anti-resonance effect. The invention realizes ultralow transmission loss, large mode field area and high nonlinear threshold, and is suitable for the application fields of mid-infrared laser transmission, gas sensing, spectral analysis and the like.

A laser apparatus for generating a sub- 190 nanometer laser beam includes a deep-ultraviolet solid-state laser source to generate an initial deep-ultraviolet laser beam, at least one mid-infrared solid-state laser source to generate at least one respective mid-infrared laser beam, and at least one lithium triborate crystal to generate an output deep-ultraviolet laser beam from the initial deep-ultraviolet and mid-infrared laser beams via sum-frequency generation. Each mid-infrared solid- state laser source includes (a) a holmium-, thulium-, or chromium-doped gain crystal or gain fiber or (b) an optically-pumped semiconductor gain material to generate the respective mid-infrared laser beam. The laser apparatus may be configured for continuous-wave and pulsed operation, thus offering versatile solutions for applications requiring DUV laser radiation below 190 nanometers. Advantageously, the present approach relies on lithium triborate. Lithium triborate crystals can be grown with the quality and dimensions needed for industrial applications.

The invention discloses a tunable mid-infrared fiber laser with high power flatness. A pumping source enters an erbium-doped fiber through a pumping / signal coupler, and a low-reflectivity cavity mirror, the erbium-doped fiber, a laser collimator and a tuned filter form a laser resonant cavity; the low-reflectivity cavity mirror and the pumping / signal coupler are coupled to output intermediate infrared laser, the tuning filter device is used for realizing a wavelength tuning function, and the insertion loss difference value of the device under different working wavelengths is less than 0.5 dB; the wavelength of the pumping source is in a 1.6-1.7 micron wave band, erbium ions are pumped from a ground state energy level to a laser upper energy level, and laser lower energy level particles are consumed; the stable insertion loss in the process of adjusting the working wavelength by using a tuning filter device is combined with the characteristics that the emission cross section and the absorption cross section of erbium ions are gradually reduced along with the increase of the wavelength and the reduction rate of the absorption cross section is greater than that of the emission cross section, so that the gain difference caused by the emission cross section difference under different laser wavelengths of the fiber laser is reduced; and the power flatness of the fiber laser under different tuning wavelengths is improved.

A method of closing an opening in a tissue comprises providing a light absorbing material, introducing the light absorbing material into a tissue opening, and irradiating the light absorbing material with at least one light source so as to increase a temperature of the light absorbing material, causing the tissue edges of the tissue opening adhere to the light absorbing material and / or to each other. A kit comprising a light absorbing material and a light emitting device is also described.

The application relates to a medical mid-infrared hollow-core optical fiber transmission device, which comprises an optical fiber body, an end cap and a connecting structure, the optical fiber body has an output end, the end cap has a connecting surface for being connected with the output end of the optical fiber body, the end cap is made of a biocompatible inorganic non-metallic material, the infrared absorption cutoff wavelength of the end cap is greater than 6 mu m, and the transmittance in the 2-6 mu m wave band is greater than or equal to 50%, the connecting structure comprises a glass sealing element, the glass sealing element is arranged at the connecting surface of the output end of the optical fiber body and the end cap, the glass sealing element and the outer peripheral surface of the output end of the optical fiber body form a ring-shaped contact interface, and the glass sealing element is fused between the output end of the optical fiber body and the connecting surface of the end cap, so that the optical fiber body and the end cap are in sealed connection. The application meets the diversified requirements of different operation scenes on the mid-infrared laser wave band, the material itself is non-toxic and stable, and the safety of the interventional laser operation is ensured.