67 results about "Thermal lensing" patented technology

The invention discloses a laser resonant cavity thermal drift suppression method and system and a laser, relates to a thermal lens effect and cavity length drift adaptive compensation technology of a high-power laser system, and aims to solve the problems of low cavity length adjustment sensitivity and slow response speed in the prior art. The method comprises the following steps: monitoring the central wavelength of a Raman Stokes spectral line in a laser resonant cavity in real time by adopting a spectral analysis module and obtaining the drift distance of the Raman Stokes spectral line; the FPGA controller determines the cavity length compensation amount of the laser resonant cavity according to the drift distance; and the FPGA controller controls the piezoelectric actuator according to the cavity length compensation amount to adjust the cavity length of the laser resonant cavity in real time so as to suppress thermally induced wavelength drift. The laser comprises a pumping source, a laser resonant cavity, a crystal arranged in the laser resonant cavity and a laser resonant cavity thermal drift suppression system, pumping light generated by the pumping source enters the laser resonant cavity, and Stokes light output by the laser resonant cavity enters the laser resonant cavity thermal drift suppression system.

The invention discloses a solar spectrum frequency division combined heat and power generation system and an operation method, and relates to the technical field of renewable energy sources, and the method comprises the following steps: S001, building a coupling analysis baseline among irradiation parameters, heat distribution and optical characteristics, collecting the real-time temperature data and light beam wavefront information of a spectrum frequency divider under the condition of sun illumination, and calculating the real-time temperature data and light beam wavefront information of the spectrum frequency divider; and generating an estimated atlas of refractive index gradient distribution based on a thermally induced refractive index change rule. Through heat, light and force coupling control, accurate prediction, real-time identification and dynamic correction of the thermal lens effect are achieved, a closed-loop feedback mechanism is established, stable alignment of photoelectric and photo-thermal paths is guaranteed, the system energy efficiency and operation reliability are effectively improved, and the problems of deviation, energy efficiency reduction and part damage caused by a thermal lens in the prior art are solved.

The invention discloses a cavity parameter optimization method for a bicrystal regeneration amplification structure. The bicrystal regeneration amplification structure to be optimized comprises an optical resonant cavity, two gain crystals arranged in the optical resonant cavity, a pumping source, a pumping light path system matched with the gain crystals, an optical switch arranged in the optical resonant cavity and a reflector used for forming the resonant cavity, the method comprises the following steps: determining the relative position and spacing of two gain crystals in an optical resonant cavity; calculating and designing the physical cavity length of the optical resonant cavity according to the electro-optical switch response time of the optical switch; the curvature radius of the reflector is calculated and selected according to the thermal lens effect possibly generated by the gain crystals under high-power pumping, and the pumping power distribution of the pumping light path system to the two gain crystals is optimized according to the output power of the pumping source and the thermal performance of the two gain crystals. And pumping energy and heat load generated by the pumping energy are dispersed on the two gain crystals.

This invention discloses a YAG-based composite laser ceramic and its preparation method. The composite laser ceramic has a five-layer structure from top to bottom: a microstructured concave YAG transparent ceramic, an Nd:YAG transparent ceramic, a YAG transparent ceramic I, a Ce,Nd:YAG transparent ceramic, and a YAG transparent ceramic II. The microstructured concave YAG transparent ceramic is used to reduce the temperature gradient and compensate for the thermal lensing effect; the Nd:YAG transparent ceramic is used to collect the energy emitted by the microstructured concave YAG transparent ceramic and to transfer the energy; the Ce,Nd:YAG transparent ceramic is used for laser energy transfer; and the YAG transparent ceramic I and YAG transparent ceramic II are used to reduce the ceramic thermal lensing effect. It is prepared using thermal bonding technology. The composite laser ceramic of this invention emits bright yellow light near 1064 nm when excited by a laser with a pump source of 808 nm. Furthermore, the composite laser ceramic has a light-to-light conversion efficiency of 19.85% and a laser threshold of 410 mW.

The invention relates to the technical field of filter membrane processing, and discloses a preparation method and a preparation system for preparing a through-hole filter membrane by using reflective Bessel laser. The preparation system for preparing the through hole filter membrane by using the reflection type Bessel laser comprises a light beam shaping assembly and a transmission assembly, the beam shaping assembly is used for reflecting and converting the incident laser into a Bessel beam; the transmission assembly is arranged on a light path of the Bessel beam and used for transmitting a non-diffraction area of the Bessel beam to a machining station. By arranging the beam shaping assembly, the incident laser can be reflected and converted into the Bessel beam instead of being transmitted to form the Bessel beam. The reflective design can avoid energy absorption of a transmission element, and is suitable for long-time high-power processing; the reflection type design does not need to consider the transmissivity of the material, and can support the incident laser from the ultraviolet band to the infrared band; the reflective design has no thermal lens effect, and the focal depth stability of a Bessel beam diffraction-free area is high.

The application discloses a semiconductor laser chip for improving wide ridge thermal lens effect, wherein a P-type limiting layer of the chip is in a ridge table shape, and both sides of the ridge table shape are inwardly recessed grooves. Surfaces of the grooves are covered with insulating layers. The top surface of the ridge table is covered with an ohmic contact layer. A P-face electrode layer is covered on the insulating layer and the ohmic contact layer, and a hole is formed between the P-face electrode layer and the insulating layer at the groove. The semiconductor laser chip structure of the application sets both side walls of the P-type limiting layer in a ridge table shape as a recessed groove structure, thereby forming a hole structure at the groove. Since the air heat dissipation coefficient in the insulating layer and the hole is very low, the heat dissipation efficiency at the side wall of the ridge P-type limiting layer is poor, the convex temperature distribution of the P-type limiting layer in the side wall direction is eliminated, the temperature of the middle region and the edge region of the P-type limiting layer is consistent, the thermal lens effect is eliminated, and the light beam quality of the semiconductor laser is effectively improved.

A laser machining apparatus includes: a beam characteristic calculation unit that calculates a beam characteristic of laser light; an optical component temperature estimation unit that estimates an estimated temperature of an optical component based on the beam characteristic and temperature information; a thermal lens estimation unit that estimates a thermal lens amount of the optical component based on the estimated temperature; an imaging performance change estimation unit that estimates, based on the thermal lens amount, an estimated imaging performance change amount that is an amount of change in imaging performance of an imaging optical system of the machining head from before start of machining; a correction amount calculation unit that calculates a correction amount of a machining parameter based on the estimated imaging performance change amount; and a control unit that changes the machining parameter based on the correction amount during the laser machining.

The invention discloses a gradient refractive index lens-based beam shaping optical system and a design method thereof, the optical system comprises at least one divergent gradient refractive index lens and at least one convergent gradient refractive index lens, and the divergent gradient refractive index lens and the convergent gradient refractive index lens are combined and configured along the same optical axis. The arrangement sequence of the gradient refractive index lenses and the relative position relation of the gradient refractive index lenses in the optical axis direction are designed, so that the optical system forms an afocal light path structure on the whole. The optical system is used for carrying out transverse scale regulation and control on an incident light beam and realizing light beam expansion, light beam shrinkage and light beam shaping on the premise of keeping approximate collimation propagation characteristics of an output light beam. According to the structure, the thermal lens effect in high-power laser can be avoided, the stability and reliability of the system are improved, tight attachment, cascade expansion and direct coupling with optical fibers are supported, and miniaturization and integration application is facilitated.

The present invention aims to provide an optical system of a laser processing apparatus in which the energy utilization efficiency of laser light is high, and the intensity distribution shape of the laser light at an irradiation point does not change even if the focal point position deviates due to thermal lens effect, and a laser processing apparatus using the optical system of the laser processing apparatus. To achieve this aim, the laser processing apparatus for processing a work by irradiating laser light according to the present invention has an optical system having optical surfaces in which a plurality of different focal points are provided on the same optical axis, and an irradiation point of the laser light on the work is at a different position from the focal points, and the intensity distribution of the laser light on a plane perpendicular to the optical axis at the irradiation point is annular at least with the optical axis as the center.

The application relates to the technical field of continuous laser optical film, in particular to a low-heat-effect laser film and a preparation method thereof. The method comprises the following steps: designing a film system according to laser wavelengths and optical performance and simulating and optimizing; precisely polishing a substrate, ultrasonic cleaning and activating; alternately preparing high and low refractive index functional layers and interface modification layers by physical vapor deposition and atomic layer deposition, setting the interface modification layers between the adjacent high and low refractive index functional layers, forming a periodic stacking structure; and annealing treatment under an inert atmosphere at 150-300 DEG C to obtain a finished product. The method has the advantages that: phonon bridging and interface passivation are realized through nano-Al2O3 interface modification, interface thermal resistance is significantly reduced, heat accumulation and thermal lens effect are inhibited, and the laser damage threshold is improved; the process is controllable, the film layer is dense and uniform, and the method is suitable for antireflection, high-reflection or light-splitting devices of high-power continuous laser systems.

This invention provides a reliability prediction and aging screening method for InP optical communication laser chips, relating to the field of semiconductor laser manufacturing and reliability assessment technology. The method first induces a transient thermal lensing effect through asymmetric bipolar current perturbation, then uses reverse bias to clear charge interference, capturing the dynamic resistance and wavelength chirp sequence reflecting lattice dislocation climb. Subsequently, a physical failure mode database is constructed, and intrinsic thermal damping is stripped in the frequency domain, mapping degradation features to epitaxial stress relaxation and nonradiative recombination mechanisms to achieve in-depth defect fingerprint analysis. Finally, based on a physically embedded deep learning architecture, the carrier rate equation and entropy increase law are used as constraints for lifetime prediction, and the second derivative of the predicted trajectory is used to evaluate the remaining lattice structure margin. This invention solves the problems of insufficient latent defect identification and predictions violating physical laws, achieving high-precision performance grading and risk interception.

The invention relates to the technical field of laser control, and discloses a multi-dimensional state linkage carbon dioxide laser output closed-loop control method and system, and the method comprises the steps: obtaining a target output parameter and the real-time attitude data of a light guide system; determining geometric transmission limitation parameters according to the attitude data, and calculating and predicting light beam characteristics in combination with a heat effect mapping relation; if the predicted light beam characteristics do not meet the safety threshold value, executing a first strategy, and on the premise of keeping the target monopulse energy constant, adjusting the combination of the peak power and the duty ratio of the laser driving signal so as to improve the light beam characteristics; and if the threshold value is met, executing a second strategy, and performing energy compensation on the laser driving signal according to the transmission loss. Through dynamic waveform reconstruction and linear compensation, the problem of transmission limitation caused by posture change of the light guide arm and a thermal lens effect is solved, and the accuracy of laser output energy and the safety of the system are ensured.

A method for maintaining the thermal stability of a laser device, a laser device power source system, and a laser device. The method comprises: acquiring the current light-emission frequency of a light-emission pulse signal of a laser device (S202); and in response to the current light-emission frequency being less than a preset frequency threshold value, generating a preheating pulse train signal before the light-emission pulse signal is generated, wherein the total power generated by the laser device under the drive of the preheating pulse train signal and the light-emission pulse signal is kept within a preset thermal stability power interval (S204). By using the method, the thermal lensing effect of a laser device crystal can be overcome, thereby improving the thermal stability of a laser device.

The invention relates to the technical field of solid lasers, in particular to a large-energy green laser. The laser comprises a first pumping source, a first pumping coupling device, a second pumping source, a second pumping coupling device, a resonance assembly, a first frequency doubling crystal, a second frequency doubling crystal, a Q-switching device, a first crystal and a second crystal. The resonant assembly is used for forming a laser resonant cavity and further comprises a compensation device. According to the large-energy green laser provided by the invention, the thermal lens effect of the laser crystal can be weakened through the double-pumping double-crystal, so that the fundamental frequency light can be better amplified. And the arranged compensation device can also improve the overall thermal management of the laser by compensating the thermal lens effect, and is beneficial to outputting stable and high-energy laser.

The invention provides a finite element numerical simulation method based on photo-thermal lens spectrum insulating oil furfural detection, and relates to the field of numerical analysis of an insulating oil detection technology. The method comprises the following steps: constructing a geometric model comprising insulating oil containing trace furfural, an optical window and a detection plane to obtain a pump beam and a probe beam; the refractive index in the pump beam propagation process is solved; presetting extinction coefficients corresponding to the furfural with different concentrations, and obtaining photothermal effect data of the multi-concentration furfural; calculating the temperature distribution after the insulating oil absorbs energy, and describing the change relation of the refractive index along with the temperature through a thermo-optical coefficient; insulating oil temperature distribution and pump beam propagation characteristics in a steady state are obtained; solving the thermal stress of the insulating oil to the optical window sheet under the excitation of the pumping light beam; non-isothermal flowing and fluid-solid coupling behaviors of the insulating oil under the thermal lens effect are simulated, and fluid solving is carried out; the influence of the thermal lens effect on probe beam propagation is solved; and light spot distribution of the detection probe light beam is obtained.

A method for controlling a LiDAR system and a LiDAR system. The method includes directing a laminar flow of heated air over an opening window of the LiDAR system, a thermal lens effect formed due to a temperature difference between the heated air and an ambient temperature; determining one or more operational parameters of the LiDAR system or a vehicle thereof; and modifying, based on the operational parameter, a flow parameter of the laminar flow. The LiDAR system includes a window; a scanning unit and a detecting unit; a nozzle configured to direct a laminar flow of heated air over the window to induce the thermal lens effect; and a control unit configured to cause the nozzle to direct the laminar flow; determining one or more operational parameters of the LiDAR system or a vehicle equipped therewith; and modifying one or more flow parameters of the laminar flow.

This invention discloses a holmium ion-doped yttrium gadolinium oxide single-crystal optical fiber, its preparation method, and its applications, belonging to the field of laser materials and laser technology. The chemical formula of the single-crystal optical fiber is Ho. 3+ YGdO3, wherein the Ho ion doping concentration is 0.2-1.0 at.%, is a cubic C-type sesquioxide crystal structure with space group Ia-3. This crystal exhibits characteristic absorption peaks at wavelengths of 1100-1200 nm and Ho-derived absorption peaks at 2.80-2.90 μm. 3+ ion 5 I6→ 5 Broad-spectrum mid-infrared fluorescence emission with I7 level transition; this crystal possesses a wide gain bandwidth, a large emission cross section, and excellent thermal properties, making it less prone to thermal lensing and thermal depolarization under continuous or high-repetition-rate pumping of single-crystal fibers, thus ensuring high stability of laser output. It is particularly suitable for realizing broadband tunable and ultrafast mode-locked mid-infrared lasers, and has broad application prospects in laser surgery, environmental monitoring, remote sensing, and other fields.

A method of altering a refractive property of a crosslinked acrylic polymer material by irradiating the material with a high energy pulsed laser beam to change its refractive index. The method is used to alter the refractive property, and hence the optical power, of an implantable intraocular lens after implantation in the patient's eye. In some examples, the wavelength of the laser beam is in the far red and near IR range and the light is absorbed by the crosslinked acrylic polymer via two-photon absorption at high laser pulse energy. The method also includes designing laser beam scan patterns that compensate for effects of multiphone absorption such as a shift in the depth of the laser pulse absorption location, and compensate for effects caused by high laser pulse energy such as thermal lensing. The method can be used to form a Fresnel lens in the optical zone.

The application discloses a method for deducing the focal length of a crystal thermal lens. Firstly, the spot data of a measuring end are measured and corrected, so that the distance from the light outlet of a detector to a focusing lens is consistent with the actual measuring distance, and the beam waist radius of the light outlet of a detection laser is deduced. Then, in the case that a crystal is put in but not pumped, the inherent lens-like focal length of the crystal caused by clamping stress or residual stress during growth is deduced. Finally, in the case that pumping light irradiates the crystal, the spot sizes of the detection light passing through both sides of the crystal are made consistent, the total lens-like focal length value of the crystal is deduced by a curvature radius formula deduction method, the influence of the inherent lens-like focal length of the crystal caused by clamping stress or residual stress during growth is excluded by a combined lens focal length formula, and finally the thermal lens focal length value of the crystal is obtained. The application has a smaller measurement error and is suitable for the measurement of the thermal lens focal length of any strength crystal.

The application discloses a solar spectrum frequency division combined heat and power system and an operation method, and relates to the technical field of renewable energy sources, and comprises the following steps: S001, a coupling analysis baseline between irradiation parameters, heat distribution and optical characteristics is established, real-time temperature data and beam wavefront information of a spectrum frequency divider under sunlight conditions are collected, and an estimated atlas of refractive index gradient distribution is generated based on a thermal refractive index variation law. Through thermal, optical and force coupling control, the application realizes accurate prediction, real-time identification and dynamic correction of thermal lens effect, establishes a closed-loop feedback mechanism, guarantees stable alignment of photoelectric and photothermal paths, effectively improves system energy efficiency and operation reliability, and overcomes the problems of deviation, energy efficiency reduction and component damage caused by thermal lens in the prior art.

The application discloses a kind of machine learning-based all-solid-state laser thermal compensation method, device and laser, wherein the method comprises: according to the parameters of the working substance of the all-solid-state laser to be compensated and the pump light power, the lens model type is selected, the lens model type is: thin lens model or thick lens model;Thermal compensation is carried out on the all-solid-state laser using the thin lens model or the thick lens model and negative lens.The thick lens model constructed simultaneously considers the influence of temperature gradient, thermal stress and end face deformation on multi-section bonded laser crystal, can more accurately simulate the thermal lens effect of multi-section doped crystal, so as to improve the performance of all-solid-state laser.

To provide a laser amplifier in which the deformation of seed light due to a thermal lens is suppressed even if the energy of excitation light becomes high.SOLUTION: A laser amplifier includes a laser amplification medium 1b having a rectangular cross section perpendicular to an optical path of seed light, a pair of metallic blocks 2a and 2b joined to two wider surfaces 11 and 12 facing each other among four surfaces of the laser amplification medium parallel to the optical path, a pumping source that outputs pumping light for pumping the laser amplification medium, and a collimating lens that collimates the pumping light.SELECTED DRAWING: Figure 5

This invention discloses a laser frequency conversion system and method based on thermal lensing effect enhancement, belonging to the field of laser technology. The system includes a first pump source, a nonlinear frequency conversion crystal, and a second pump source. The crystal is a rare-earth-doped calcium borate crystal, which absorbs the first pump light to generate a controllable thermal lensing effect. The fundamental wave light emitted from the second pump source is coaxially incident on the crystal with the first pump light. The thermal lens focuses the fundamental wave light, significantly increasing its power density within the crystal. The crystal then utilizes a nonlinear optical effect to efficiently convert the high-power-density fundamental wave light into harmonic light output. This invention solves the problem of low efficiency in traditional extracavity frequency doubling. Through an active focusing mechanism, high-efficiency and high-stability visible light laser output can be achieved with only a lower fundamental wave power, making it particularly suitable for biological detection and medical aesthetics.

This invention proposes a gallium nitride-based semiconductor laser, comprising, from bottom to top, a substrate, a lower confinement layer, a lower waveguide layer, an active layer, an upper waveguide layer, and an upper confinement layer. This invention incorporates a multi-layered, multi-vacancy electron-phonon modulation layer within the semiconductor laser element, defining the electron affinity distribution and polarization optical phonon energy distribution characteristics of each multi-vacancy electron-phonon modulation layer. This forms single-vacancy, vacancy cluster, and multi-vacancy modulated electron-phonon structures, localizing electron-phonons between the lower confinement layer and the lower waveguide layer. This reduces the Stokes shift caused by the photon energy difference between the pump light and the oscillating light, reduces heat loss from phonon vibration and phonon transport, improves the heat dissipation of the laser element, mitigates interlayer thermal mismatch, suppresses the thermal lensing effect and stress birefringence effect of the laser, improves laser beam distortion and depolarization, and enhances the laser beam quality factor.

To provide a Tb-containing rare earth-aluminum garnet ceramic which has a Verdet constant similar to that of a TGG single crystal used in an isolator, has an insertion loss and extinction ratio equal to or greater than those of a TGG single crystal, generates less heat when a high-power laser is applied thereto, and is unlikely to cause a thermal lens effect or thermal birefringence. The present invention relates to: a Tb-containing rare earth-aluminum garnet ceramic including a garnet polycrystal represented by the compositional formula (TbxRe1-x)3(AlySc1-y)5O12 wherein Re is at least one element selected from a group consisting of Y and Lu, x=1.0-0.5, and y=1.0-0.6, and including Si and at least one element selected from a group consisting of Ca and Mg; a method for producing same; and an isolator device obtained using the ceramic.

The application relates to a picosecond laser with high beam quality, comprising: a pump source for providing pump energy to an amplification crystal; a laser oscillator for providing high-beam-quality signal light to the amplification crystal; the amplification crystal for realizing amplification of signal light power; a pump light shaping system, which comprises a first lens group formed by a first plano-convex lens and a second plano-convex lens and a third plano-convex lens arranged at intervals with the first lens group, the pump light is subjected to quasi-collimation processing through the first lens group, and then is focused through the third plano-convex lens arranged at intervals, so that the Rayleigh length of the focused pump light completely falls in the amplification crystal; and a signal light shaping system, which comprises a fourth plano-convex lens arranged on the upstream of the light path of the amplification crystal and a second lens group formed by a fifth plano-convex lens and a first plano-concave lens, the signal light is focused through the fourth plano-convex lens, and then is subjected to expansion collimation through the second lens group, so that the Rayleigh length of the signal light completely falls in the amplification crystal, the pump light and the signal light are in a uniformly distributed state in the amplification crystal, the amplification crystal generates uniform heat distribution, the thermal lens effect is eliminated, the occurrence probability of the thermal birefringence effect and the thermal distortion effect is reduced, and the amplification efficiency of the light beam and the quality of the output light beam are greatly improved.

A high-power laser system includes at least one high-power laser source outputting a substantially single mode (SM) beam. The SM beam is coupled into a reflective volume Bragg grating (RVBG) made of material which absorbs the SM beam to induce a first thermal lens (TL). Upon reflecting, the beam exits the RVBG through the first TL and is coupled into an optical compensator made from material different from that of the first TL and inducing a second TL. The second TL is configured to have a power opposite to that of the first TL matching to that of the first TL to at least partially compensate heat induced thermal degradation of the reflected beam by the first TL.

The invention relates to a magneto-optical isolator with a low thermal lens effect, in particular to the technical field of optical instruments. The device comprises an optical fiber collimator, a first polarized light beam splitter, a neodymium iron boron permanent magnet, an optical rotation crystal, a wave plate, a second polarized light beam splitter, a concave lens and a convex lens which are sequentially arranged along a light forward transmission path, wherein the optical rotation crystal is a CS: CaFoptical rotation crystal.

The invention relates to a repetition-frequency adjustable high-beam-quality laser, and the laser comprises a seed source which outputs picosecond signal laser with the repetition frequency of 20-100 MHz; the pulse selector is connected with the seed source and is configured to respond to a target repetition frequency value set by a user, perform conventional pulse selection when the repetition frequency is greater than 50kHz, start a Burst Mode editing function when the repetition frequency is less than or equal to 50kHz, and generate a pulse string envelope containing 2-10 sub-pulses; the three-stage series laser amplifier is used for amplifying the power of the pulse, and each stage comprises a pumping source, a focusing lens and a laser crystal; the thermal lens cooperative control unit is used for improving the thermal lens effect of the laser crystal and comprises a pumping light spot adjusting module which responds to the target repetition frequency value and automatically adjusts the distance from each stage of focusing lens to the laser crystal and the pumping current; the pulse energy editing module is used for dynamically modulating sub-pulse energy in the pulse string under the Burst Mode to enable the sub-pulse energy to be distributed progressively; the uniform temperature field module comprises a TEC array and a temperature sensor array which are arranged around the laser crystal, the laser crystal temperature field set value is automatically matched according to the target repetition frequency value, and the uniformity of the laser crystal temperature field is maintained. The thermal lens effect and the thermal balance in the laser crystal are stable, and the laser can stably output laser beams with excellent beam quality.