170 results about "Quantum cascade laser" patented technology

The invention discloses an on-line detection method for volatile organic compounds in waste gas, and belongs to the field of waste gas emission monitoring, the detection method comprises the following specific steps: I, starting a quantum cascade laser frequency comb of a middle infrared band, calibrating various parameters of the quantum cascade laser frequency comb, and ensuring to cover a characteristic absorption area of the volatile organic compounds in the waste gas; iI, inputting the waste gas into a gas detection chamber through a sampling pipeline, monitoring the state of the waste gas in real time, and dynamically adjusting the conditions of the gas detection chamber according to various collected signals; the device can capture instantaneous fluctuation of waste gas concentration in real time, meets the high-speed dynamic emission monitoring requirement, has extremely high coherence and narrow linewidth, can analyze tiny spectral line differences which cannot be distinguished by a traditional spectrograph, remarkably improves the detection precision and the recognition capability, ensures that a measurement result still keeps consistency and high reliability under different working conditions, and is suitable for large-scale popularization and application. The signal-to-noise ratio is obviously improved, the power drift is reduced, and long-time stable operation is realized.

In order to provide an IR-QCL element which utilizes the characteristics of a ZnO-based semiconductor material, the present disclosure discloses a quantum cascade laser element 1000 that has a plurality of unit structures 10U in each of which a well layer of ZnO or ZnMgO and a barrier layer of ZnMgO or MgO are alternately and repeatedly stacked. Each unit structure includes a light emitting layer 10E and a continuum layer 10C. The light emitting layer includes: an upstream well layer 10W1 that is composed of a step quantum well having a first layer and a second layer, which have different MgO composition ratios from each other; and a downstream well layer 10W2 that has a smaller MgO composition ratio than any of the first layer and the second layer.

The invention relates to a wavelength-switchable, semiconductor laser (10), for generating of laser light in the optical range between 1 μm and 100 μm, wherein the laser (10) comprises an external cavity (11) and at least the following components: a semiconductor optical amplifier (12), comprising an intra-cavity facet (121) facing towards; a first optical element (13) for collimating a laser beam exiting the intra-cavity facet (121) arranged at the intra-cavity facet (121) of the semiconductor optical amplifier (12); a transmissive, wavelength-adjustable interference filter (1), comprising at least i) a wavelength-adjustable Fabry-Perot filter (100) and ii) a Fabry-Perot etalon (110) comprising a first planar surface (111) and a second planar (112) surface, wherein the first and second surface (111, 112) of the etalon (110) are arranged opposite and plane-parallel to each other and delimit an etalon cavity (113); wherein the Fabry-Perot etalon (110) and the Fabry-Perot filter (100) are arranged in a row; wherein the interference filter (1) is arranged between the first optical element (13) and the beam splitter (14), and wherein the components are arranged such that laser light comprising a selected laser wavelength can stably resonate in the external cavity, wherein an on-axis, retro-reflecting beam splitter (14) is arranged at one end of the external cavity (11). Furthermore, the invention relates to a method for selecting a laser wavelength using the laser.

The invention provides an ultrahigh strain material component and thickness control method for a quantum cascade laser, and relates to the technical field of semiconductor lasers. The control method is based on a strain compensation calibration method, a first superlattice layer and a second superlattice layer which are the same in thickness are constructed, a strain balance superlattice is formed, it is guaranteed that the whole epitaxial layer is free of strain relative to a substrate, the problem that the growth thickness of a large-strain material is small is solved, the peak position accuracy and the peak intensity during XRD testing are further improved, and the test accuracy is improved. And the half-peak width is narrow, so that the accuracy of the components of the backstepping material is improved.

For at least partial fabrication of a mirror for an optical cavity, a surface to be processed of an optical substrate is positioned in an operating plane, which is equal to or parallel to a focal plane of a laser arrangement, and a concave surface profile of the surface is generated by applying a sequence of multiple laser shots to the surface by using a quantum cascade laser of the laser arrangement.

The invention discloses a system and a method for detecting furfural in transformer oil based on a photo-thermal lens spectrum. A quantum cascade laser is used as pumping laser, and a helium-neon laser is used as detection laser; a visible light-infrared light dichroscope, a chopper, a reflector, an attenuator, a plano-convex lens, a fixed optical path liquid pool, an iris diaphragm, a photoelectric detector, a lock-in amplifier, an upper computer and the like are arranged, so that in-situ rapid, accurate and high-sensitivity quantitative detection of trace furfural in the transformer oil is realized; through the pumping laser covering the infrared characteristic absorption spectral line in furfural, trace furfural molecules in the transformer oil absorb the pumping laser with the average power exceeding 100 mW to excite a strong thermal lens effect, and the detection performance is remarkably improved; in-situ and rapid detection of furfural in the transformer oil is realized by utilizing a thermal lens effect generated by absorption of furfural in the transformer oil on mid-infrared light.

The invention relates to a quantum cascade laser with a cylindrical waveguide and a preparation method thereof, and belongs to the field of photoelectron, the quantum cascade laser comprises a laminated structure, the laminated structure is provided with two waveguide grooves, a ridge waveguide is formed between the two waveguide grooves, the waveguide grooves are hyperbolic, and the ridge waveguide is cylindrical; the bottom and side wall areas of the waveguide groove are subjected to mechanochemical grinding treatment and filled with InP: Fe, then mechanochemical grinding is carried out again, and then an insulating film layer material is evaporated; due to the unique cylindrical shape of the ridge waveguide, the photon density can be effectively improved, and the output characteristic of laser is optimized; and meanwhile, the mode distribution of light can be better controlled, and excellent laser characteristics are realized by utilizing optical reflection and interference effects. According to the invention, before secondary epitaxy, a mechanochemical grinding method is adopted to carry out surface treatment on the double channels, so that waveguide loss after secondary epitaxy of InP: Fe can be effectively reduced, the threshold current density is further reduced, and the output power and the slope efficiency are increased.

The invention provides a gas concentration detection method, a gas concentration detection device and electronic equipment. The method comprises the following steps: acquiring a spectral signal obtained by detecting to-be-detected gas in a gas cell by a quantum cascade laser under preset sampling parameters; calculating search direction information and search distance information according to the spectral signal and the initial matrix; calculating a transition matrix according to the spectral signal, the search direction information and the search distance information to remove redundant information in the spectral signal; under the condition that a change value between the transition matrix and the initial matrix meets a preset threshold value, determining the transition matrix corresponding to the change value as a target matrix; performing calculation and filtering processing on the target matrix and a preset reference signal to obtain a direct current filtering signal related to the direct current signal; performing signal conversion processing on the direct current filtering signal to obtain a target harmonic signal; and inputting the target harmonic signal into a gas concentration prediction model, and outputting gas concentration information of the to-be-detected gas.

The invention discloses an output wavelength closed-loop adjustment method and system based on a negative feedback adjustment device, and relates to the field of external cavity quantum cascade lasers. According to the output wavelength closed-loop adjusting method, during the working period of the external cavity wide-spectrum tuning laser, the real-time light spot position is calculated through a negative feedback adjusting device, the real-time light spot position is matched with the light spot position in a calibration data table to obtain the corresponding laser wavelength, and the output wavelength is adjusted by comparing the laser wavelength with the target laser wavelength. Determining a voltage adjustment value, controlling the current working voltage of the galvanometer driver to be increased or decreased according to the voltage adjustment value, and circulating the process until the laser wavelength output by the resonant cavity is stabilized in the target laser wavelength or an allowable error range thereof; accurate control over the rotating angle of the galvanometer is achieved, and repeatability and accuracy of the output wavelength are improved.

The invention provides a high-power external cavity tunable quantum cascade laser output module. The high-power external cavity tunable quantum cascade laser output module comprises a first lens, a first half-wave plate and a first mid-infrared grid polaroid which are sequentially arranged along a light path of a first laser; a second lens, a second half-wave plate, a second mid-infrared grid polarizer and a third half-wave plate are sequentially arranged along the light path of the second laser; emergent light of the first mid-infrared grid polaroid and the third half-wave plate is converged on different surfaces of the third mid-infrared grid polaroid, the first blazed grating is arranged on a reflection light path of the first mid-infrared grid polaroid, and the second blazed grating is arranged on a reflection light path of the second mid-infrared grid polaroid. According to the invention, the problems of wavelength locking and low polarization beam combination efficiency caused by insufficient polarization state of the quantum cascade laser can be effectively solved, narrow linewidth output and wavelength tuning of the quantum cascade laser can be realized, and even high-power dual-wavelength tunable output can be realized through polarization beam combination structure expansion.

The invention discloses an in-plane heterogeneous photonic crystal quantum cascade laser. The in-plane heterogeneous photonic crystal quantum cascade laser comprises a back metal electrode, a front metal electrode and an epitaxial wafer located between the back metal electrode and the front metal electrode. Wherein a photonic crystal layer is arranged between the epitaxial wafer and the front metal electrode; wherein the photonic crystal layer is composed of first-order photonic crystals, symmetrical bilattices and second-order photonic crystals which are periodically arranged and are sequentially symmetrical from outside to inside. The problems of low modal selectivity, low coupling efficiency and the like of the existing wide ridge emission QCL are solved, and a new thought is provided for researching the large-area QCL with high power and light beam quality.

The invention provides a gas detection method and a gas detection device.The method comprises the steps that gas spectral data are obtained, the gas spectral data are obtained by detecting mixed gas in a gas cell through a quantum cascade laser, and the mixed gas comprises gas to be detected; according to global index information of the gas spectrum data, obtaining a plurality of local index information, the global index information representing coordinate curves of a plurality of signals in different coordinate system quadrants in the gas spectrum data; on the basis of a Hilbert space mapping method, quadrant overturning and rotation processing is carried out on a coordinate system quadrant of the at least one piece of local index information, and initial global coordinates are obtained; calculating a new initial global coordinate by taking the initial global coordinate as new global index information, and determining the new initial global coordinate corresponding to the target order of the Hilbert curve as target spectral data; and inputting the target spectral data into the gas concentration detection model, and outputting gas concentration information of the to-be-detected gas.

A quantum-cascade laser element includes: a semiconductor substrate; a semiconductor mesa formed on the semiconductor substrate to include an active layer having a quantum-cascade structure and to extend along a light waveguide direction; an embedding layer formed to interpose the semiconductor mesa along a width direction of the semiconductor substrate; a cladding layer formed over the semiconductor mesa and over the embedding layer; and a metal layer formed on the cladding layer. A pair of groove portions extending along the light waveguide direction are formed in a surface on an opposite side of the cladding layer from the semiconductor substrate. The pair of groove portions are disposed in two respective outer regions when the cladding layer is equally divided into four regions in the width direction of the semiconductor substrate. The metal layer enters the pair of groove portions.

The laser module includes a QCL element, a MEMS diffraction grating, a lens holder for holding a lens disposed between the QCL element and the MEMS diffraction grating, and a package. The package includes a bottom wall, a side wall erected on the bottom wall and formed in an annular shape so as to surround a region in which the QCL element is accommodated, and a top wall closing an opening of the side wall on a side opposite to a side where the bottom wall is disposed. The top wall faces the bottom wall in a direction orthogonal to the optical axis direction of the lens, and the distance between the top wall and a surface of the lens holder on a side where the top wall is disposed is smaller than a thickness of the lens holder along the optical axis direction of the lens.

The invention belongs to the technical field of laser spectrum, and particularly relates to an intermediate infrared spectrum cavity ring-down system based on a quantum cascade laser. In order to overcome the wavelength drift of the laser and improve the accuracy of gas concentration measurement, a light beam emitted by the quantum cascade laser passes through two isolators and is divided into two light beams through a beam splitter, and the light with relatively low light intensity is reflected by a transmitting mirror, passes through a standard gas pool and a focusing lens and is emitted into a first detector to obtain a direct absorption signal. The light with higher light intensity is reflected by the gold film reflector, enters the optical resonant cavity and is driven into the second detector through the focusing lens, the signal is interrupted through DG535 to obtain a ring-down time signal, and the ring-down time signal is processed through a program to obtain a gas absorption signal. A direct absorption signal of the first detector is collected, a polynomial is used for fitting the absorption signal, each parameter of the fitting polynomial is obtained, and the fitting polynomial is used for fitting the signal obtained by the second detector.

The invention discloses a long-optical-path CO2 optical cavity and a detection device, the optical cavity comprises a conical cavity, the longitudinal section of the conical cavity is trapezoidal, and the inner wall of the conical cavity is provided with a silver layer. The detection device comprises the optical cavity, a quantum cascade laser, a collimating lens, an air inlet, an air outlet, a mercury cadmium telluride detector, a digital signal processor (DSP), an air pressure controller and an air pressure sensor. The air inlet is connected with the small end face of the optical cavity and controls the air inlet amount through the proportional valve and the first electromagnetic valve, the air outlet is formed in the large end face of the optical cavity and connected with the second electromagnetic valve and the air pump, and two laser signals with different wavelengths emitted by the quantum cascade laser respectively pass through the collimating lens and then enter a cavity body of the optical cavity at a set angle. A signal emitted by the optical cavity is detected by the mercury cadmium telluride detector and then is input into the DSP for processing, and the CO2 concentration is calculated according to a predetermined model in the DSP. According to the invention, intelligent and automatic detection can be realized, the detection efficiency and accuracy are improved, and manual intervention and errors are reduced.

The present invention discloses an anti-reflection quantum cascade laser based on a tilted surface high-order grating. The cross-section of the laser in the x-direction and the y-direction is a transverse structure, and is provided with an N-type electrode, an InP substrate, an n-type doped lower cladding, an n-type doped lower limiting layer, an active layer (the active layer includes multiple cascade periods, each cascade period includes an injection region and an active region), a p-type doped light limiting layer, a p-type doped cladding, a ridge waveguide layer, and a surface metal electrode layer in sequence from bottom to top; the longitudinal structure of the laser is the z-direction, which is composed of an FP resonant cavity formed by a natural cleavage surface of the laser and a tilted surface high-order grating located in the FP resonant cavity; the z-direction is the optical resonance direction of the laser. The present invention has the advantages of simple structure, simple grating manufacturing process, low cost (compared with ordinary gratings), etc., and can improve the working stability and reliability of the quantum cascade laser after coupling and packaging with a micro-optical element.

An external resonance-type laser module includes: a quantum cascade laser; a MEMS diffraction grating including a movable portion capable of swinging around an axis and a diffraction grating portion formed on the movable portion; a lens; a magnet; and a yoke. The MEMS diffraction grating includes a pair of coils respectively disposed on one side and the other side with respect to the axis when viewed in a normal direction parallel to a normal line of the diffraction grating portion, and each of the pair of coils includes an inside part extending along the axis. A recess portion is formed in the magnet, and at least a part of the recess portion overlaps the inside part when viewed in the normal direction.

The invention relates to the technical field of photon integration, in particular to an on-chip integrated quantum cascade laser optical frequency comb and a preparation method thereof. The quantum cascade laser optical frequency comb comprises a silicon waveguide and a quantum cascade laser integrated on the silicon waveguide through a micro transfer printing technology. A fundamental mode of an active area waveguide of the quantum cascade laser is coupled with a fundamental mode of a silicon waveguide to excite an antisymmetric mode, and the antisymmetric mode has the characteristic of small negative dispersion, so that regulation and control of dispersion in a quantum cascade laser cavity can be realized, and generation of an optical frequency comb can be realized. According to the invention, efficient integration of the quantum cascade laser on the silicon waveguide is realized, accurate regulation and control of dispersion of the quantum cascade laser can be realized through integration of micro transfer printing and the silicon waveguide, and a solid dispersion basis is provided for generation of an optical frequency comb of the quantum cascade laser. And the quantum cascade laser subjected to micro transfer printing is of a buried structure, so that the heat dissipation performance is improved.

The present application relates to a kind of growth parameter calibration methods of strain compensation quantum cascade laser material, the active region of the quantum cascade laser material In x Ga 1‑x As / In y Al 1‑y As multi-quantum well, wherein 0.53 < x < 1, 0 < y < 0.52, by growing InGaAs debugging structure, InGaAs calibration structure, InAlAs debugging structure, InAlAs calibration structure, obtain growth parameter In x Ga 1‑x As growth rate and In y Al 1‑ y As growth rate.The method of the present application grows strain compensation InGaAs / InAlAs quantum cascade laser material, and the epitaxial efficiency and accuracy are improved.

The invention discloses a mid-infrared laser based on three-device on-chip integration and a preparation method thereof, relates to the crossing field of a semiconductor laser technology and an optical communication technology, and solves the problem that the existing quantum cascade laser QCL technology cannot give consideration to both high modulation rate and high power. An intermediate infrared laser comprises a QCL unit, an EAM unit and an SOA unit which are sequentially arranged on a substrate. The substrate comprises a semi-insulating InP (Indium Phosphate); the QCL unit, the EAM unit and the SOA unit share the same ridge-shaped waveguide structure and grow through epitaxy butt joint. The method provided by the invention is suitable for a mid-infrared band space communication scene with high requirements on the laser modulation rate, the output power and the single-mode stability.

To provide a quantum cascade laser capable of simplifying a structure and improving a strength.SOLUTION: A quantum cascade laser 1 includes: a semiconductor substrate 2 having a first surface 2a and a second surface 2b; a semiconductor stacked body 3 that includes an active layer 31 having a cascade structure and is formed on the first surface 2a of the semiconductor substrate 2; a first electrode 4 formed on a surface 3b of the semiconductor stacked body 3; and a second electrode 5 formed on the second surface 2b of the semiconductor substrate 2. The semiconductor substrate 2 is an InP substrate with a carrier density of 1×1017 cm-3 or less. A concave portion 21 that passes through the semiconductor substrate 2 and reaches the semiconductor stacked body 3 is formed in the second surface 2b of the semiconductor substrate 2. The second electrode 5 is continuously formed on the second surface 2b of the semiconductor substrate 2, on side surfaces 22 of the concave portion 21, and on an exposed surface 3a of the semiconductor stacked body 3 which is exposed from the semiconductor substrate 2 at a bottom 21a of the concave portion 21.SELECTED DRAWING: Figure 2

The invention relates to the technical field of lasers, in particular to a quantum cascade laser chip temperature acquisition method and system. The method comprises the following steps: mounting at least one temperature sensor on one side, close to a light emitting junction of a laser, of a heat sink, collecting real-time temperature values through the temperature sensor, preprocessing the plurality of temperature values, and calculating the real-time temperature of the laser based on a plurality of first temperature values obtained after preprocessing through a moving average method. According to the method, a high-precision temperature sensor is mounted close to a quantum cascade laser chip, so that the problem of monitoring lag of the chip temperature due to the fact that an existing quantum cascade laser tube core temperature detector is far away from a luminous junction is solved.

This invention relates to a dual-comb control system for a terahertz quantum cascade laser, comprising a first terahertz quantum cascade laser, a second terahertz quantum cascade laser, a first T-type biaser, and a second T-type biaser. The first terahertz quantum cascade laser operates in optical frequency comb mode, while the second terahertz quantum cascade laser operates above a threshold current. The first and second terahertz quantum cascade lasers emit terahertz light from each other. The first terahertz quantum cascade laser also functions as a detector to detect a mixing signal. The state of the mixing signal is switched by changing the power of the radio frequency signal generated by the radio frequency source. This invention enables the switching of the mixing signal between chaotic, unstable, and dual-comb states under high drive current, significantly improving the spectral width and application scenarios of the dual-comb system based on the quantum cascade laser.

The invention relates to a quantum cascade laser emitting a polarized TM optical mode with a wavelength between 3 and 15 µm, comprising an amplifying medium and a main waveguide. The latter includes a coupling section in contact with the amplifying medium, comprising a diffraction grating (DFB). The coupling section has a width greater than or equal to a minimum width from which an antisymmetric supermode propagating in a laser guidance structure comprising the amplifying medium and the main waveguide has a confinement factor in an active region of the amplifying medium strictly greater than those of the optical modes capable of being guided by the guidance structure. The main waveguide comprises a core based on atoms from column IVA of the periodic table of elements and a confinement subshell of SiN or a chalcogenide. (See Figure 1A for the abstract.)

Quantum cascade laser device comprising a hollow housing (2) with an exit window (8) for emitting laser light (L) to the outside; the housing (2) contains: a heat sink (4); a submount (5) that is attached to the heat sink (4); a quantum cascade laser element (6) mounted on the submount (5); and a cover element (7) opposite the submount (5) which is to be arranged between an emission end surface (6a) of the quantum cascade laser element (6) and the exit window (8) and which has a light absorption property for the laser light (L) emitted by one emission end surface (6a) and another emission end surface (6b) of the quantum cascade laser element (6); wherein the emission end surface (6a) of the quantum cascade laser element (6) and a surface opposite the cover element (7) in the submount (5) are flush with each other; the cover element (7) has an opening (18) which is arranged at a position opposite one emission end surface (6a) in order to direct laser light (L) through it in the direction of the exit window (8); the opening (18) has: a cone-shaped first opening part (21), the diameter of which increases from the side of one emission end surface (6a) to the side of the exit window (8), a second opening part (22) with a fixed diameter that is not smaller than the smallest diameter of the first opening part (21) on the side of one emission end surface (6a) of the first opening part (21), and a third opening part (23) with a fixed diameter for positioning a lens (24), wherein the diameter of the third opening part (23) is larger than the largest diameter of the first opening part (21), wherein the third opening part (23) is located on the side of the exit window (8) and wherein a lens (24) is inserted into the third opening part (23) so that the laser light (L) emitted from the emission end surface (6a) and passing through the opening (18) exits the housing (2) through the exit window (8).

An analysis device that irradiates a measurement cell into which a sample has been introduced with light, detects light having passed through the measurement cell, and analyzes a component to be measured contained in the sample, the analysis device includes: two or more laser light sources selected from a first laser light source that is a quantum cascade laser, a second laser light source that is an interband cascade laser, and a third laser light source that is a semiconductor laser other than the quantum cascade laser and the interband cascade laser; a photodetector that detects light emitted from each of the laser light sources and having passed through the measurement cell; and a light source control unit that causes the laser light sources to perform pulse oscillation at different timings.

A QCL includes a gain region that generates radiation. An optical waveguide feeds the radiation back to the gain region. A first order and / or a second order Bragg reflector are formed in the optical waveguide. The first order Bragg reflector narrows a spectrum of the radiation. The second order Bragg reflector outcouples the radiation through a large facet.

The application relates to a method of testing an item with a spectrally precise, artificial solar spectrum including wavelengths from 200 nm to 20 microns and it also relates to a solar spectrum simulator capable of producing a light spectrum including wavelengths from 200 nm to 20 microns. The simulator comprises: a) amplitude optimization software; b) a spectrum controller; c) an emitter controller; d) heat lamp / heater generation sources including: a xenon / infrared (IR) lamp and a blackbody radiator; e) laser generation sources including an ultraviolet (UV) laser source, a visible laser source, a near infrared (NIR) laser source, a short wavelength (SW) laser source, a medium wavelength (MW) laser source, a long wavelength (LW) laser source, and a quantum cascade laser source (QCL); f) a beam combiner; g) a beam profiler; h) a spectrometer; and i) a surface on which can be placed an item to be tested.

The invention discloses an annular micro-cavity quantum cascade laser. The laser comprises substrates which are sequentially arranged from bottom to top; the annular microcavity is arranged on the substrate, the annular microcavity is an elliptical resonator with a notch, and a groove is formed in the central area of the annular microcavity; the semi-insulating InP: Fe filling layer is arranged in the groove in the central area of the annular microcavity, and the difference between the resistivity of the semi-insulating InP: Fe filling layer and the refractive index of the upper cladding and the contact layer is less than 1%; the supporting ridges are arranged on the substrate, and the two supporting ridges are arranged on the two sides of the annular microcavity and are as high as the annular microcavity; the coplanar electrode comprises a central electrode arranged on the upper surface of the annular microcavity and grounding electrodes symmetrically arranged on the outer surface of the supporting ridge structure, and the central electrode and the grounding electrodes are the same in height. The quantum cascade laser has high-frequency modulation performance, improves heat dissipation performance, and has high response rate.