88 results about "Thermal lensing" patented technology

The gallium nitride-based semiconductor laser comprises a substrate, a lower limiting layer, a lower waveguide layer, an active layer, an upper waveguide layer and an upper limiting layer which are sequentially arranged from bottom to top. According to the semiconductor laser element, the multi-vacancy electron phonon regulation and control layers of a multi-layer structure are arranged in the semiconductor laser element, and the electron affinity distribution characteristic and the polarization optical phonon energy distribution characteristic of each multi-vacancy electron phonon regulation and control layer are limited, so that single-vacancy, vacancy group and multi-vacancy regulation and control electron phonon structures are formed; the electron phonons are localized between the lower limiting layer and the lower waveguide layer, stokes frequency shift formed by photon energy difference between pump light and oscillation light is reduced, phonon vibration and phonon transport heat loss are reduced, the heat dissipation performance of a laser element is improved, thermal mismatch between epitaxial layers is improved, the thermal lens effect and stress birefringence effect of the laser are inhibited, and the laser efficiency is improved. The problems of laser beam distortion and depolarization are improved, and the laser beam quality factor is improved.

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 belongs to the field of solid lasers, and particularly relates to a laser for realizing high-power pump beam quality enhancement based on multi-stack heat transfer, which comprises a pump module, a pump shaping coupling module, a multi-stack crystal, a cube-corner prism, an output mirror and a cooling device. And the multi-laminated crystal adopts a high-thermal-conductivity diamond film, so that transverse rapid diffusion of heat is realized, local heat accumulation and temperature rise are relieved, wavefront distortion and a thermal lens effect caused by thermally induced refractive index change are reduced, and the stability of a laser mode is improved. The cube-corner prism is used as a resonant cavity mirror surface, can automatically compensate angle deviation, optimizes mode matching in the cavity, has a synergistic effect with a zigzag total internal reflection path in the crystal, further balances a heat affected zone, improves light field distribution, and remarkably improves light beam uniformity, stability and TEM00 mode quality. The structure is high in adaptability, is suitable for various wavelengths, pumping modes and thermal loads, and assists the laser to realize miniaturized, high-integration and high-performance output.

The invention discloses a programmable waveform modulation high-power optical fiber laser system, particularly relates to the field of high-power optical fiber lasers, and is used for solving the problem of power monitoring and control instability caused by alias distortion under high pulse repetition frequency. Micro-amplitude random time jitter is implanted, sampling and pulse rhythm coupling are scattered through synchronous mapping of a time mark and a power sequence, and turn-back pseudo fluctuation is blocked from the source; the abstract evaluation mechanism fuses energy domain and time domain features, and uses a single determination identifier to drive sampling frequency adaptive migration, so that a monitoring link is continuously in a co-prime fraction ratio operation interval, and alias distortion root causes are eliminated; the sampling label and the judgment identification jointly trigger a feed-forward gain matrix to form a monitoring evaluation adjustment compensation closed loop, power aftershock is reduced in real time, stimulated scattering and thermal lens linkage amplification are inhibited, and light beam quality stability and energy smooth distribution are maintained.

The invention discloses a device and method for testing performance degradation of a deep ultraviolet fused quartz material, and the method comprises the steps: employing a continuous laser beam with the wavelength of 213nm as a detection light beam, and simultaneously monitoring the transmittance change of the detection light beam after the detection light beam passes through a deep ultraviolet laser irradiation region of the deep ultraviolet fused quartz material and the instantaneous change of the light intensity of a light beam central region; the color center defect concentration change of the deep ultraviolet fused quartz material caused by deep ultraviolet laser irradiation and the absorption change of the deep ultraviolet laser irradiation wavelength are obtained, and the transmittance change of the irradiation laser beam transmitting the deep ultraviolet fused quartz material is monitored at the same time; the performance degradation data of the deep ultraviolet fused quartz material under the irradiation of the deep ultraviolet laser and the contribution of the color center defect generated by the irradiation of the deep ultraviolet laser to the performance degradation are obtained. According to the invention, the contribution of color center defects to performance degradation can be distinguished, the performance recovery mechanism of hydrogen can be measured, and the measurement sensitivity of thermal lens signals can be effectively improved.

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 mid-infrared nonlinear crystal, a mid-infrared laser and a preparation method of the mid-infrared nonlinear crystal, a slice crystal is adopted, an included angle theta is formed between an optical axis Z axis of the slice crystal and the surface, the slice crystal is polarized into a periodic polarization structure with the period of lambda through a room temperature electric field polarization technology, and a large surface forms an optical plane through polishing. The problem of how to reduce the thermal lens effect of the intermediate infrared nonlinear crystal is solved, and the damage threshold of the intermediate infrared nonlinear crystal can be improved, so that the laser output power is improved.

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 present invention discloses a detection device and method for the laser thermal lens effect of an optical crystal, which relates to the field of thermal lens effect detection and includes a pump laser, a probing red laser, and a power detector. Along the beam direction of the pump laser, a beam combiner, a crystal sample stage, and a beam splitter are sequentially arranged. A front reflecting mirror is arranged in the beam direction of the probing red laser, and the front reflecting mirror is used to reflect the beam of the probing red laser towards the beam combiner, so that the beam of the probing red laser coincides with the beam of the pump laser and passes through the optical crystal. A rear reflecting mirror is arranged corresponding to the power detector. The present invention makes the pump laser and the probing light coincide and pass through the optical crystal. By heating the optical crystal with the pump laser, the thermal lens effect of the optical crystal is induced and amplified, and then the probing light is detected, so as to clearly judge the strength of the thermal lens effect of the optical crystal, which is beneficial to the grading of the crystal quality and the improvement of the production process.

The present invention relates to the field of optical technologies, and particularly to a measuring device and a measuring method for the thermal effect parameters of a disk laser crystal. The measuring device includes a first laser, a lens group, a beam splitting prism, a fixed-focus lens, a filtering unit, an imaging unit, a standard plane mirror, and a measuring unit; the lens group and the beam splitting prism are sequentially arranged along the light output optical path direction of the first laser. The first laser is used for emitting a probe light, and the probe light is expanded and collimated by the lens group and then split by the beam splitting prism. The first transmitted light forms a reference light spot; after the first reflected light is reflected by the standard plane mirror, a second reflected light is obtained, and the measuring unit is arranged along the optical path direction of the second reflected light; after the second reflected light is transmitted by the beam splitting prism, it is reflected by the disk laser crystal and returns along the original path to form a detection light spot. The technical solution provided by the present invention can not only measure the parameters of the thermal lens effect of the disk laser crystal in the laser to be measured, but also measure the parameters of the thermal air wedge effect.

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 invention belongs to the technical field of solid lasers, and particularly relates to a laser for realizing wide-temperature adaptive enhancement based on a temperature regulation and control pumping angle, which comprises a differential heat sink system, an LD array pump, a focusing coupling system, an input mirror, a temperature regulation and control gain crystal system and an output mirror which are sequentially arranged from left to right, and a temperature regulation feedback line, a temperature feedback line and an intelligent central processing system, wherein the differential heat sink system and the temperature regulation gain crystal system are connected with the intelligent central processing system through the temperature regulation feedback line and the temperature feedback line respectively. The differential heat sink system, the temperature control gain crystal system and the intelligent central processing system are organically combined, laser gain optimization in a wide temperature range is achieved by dynamically adjusting the pumping angle and compensating the thermal focal length, and the problem of gain loss caused by the thermal lens effect during long-time work of the laser is effectively solved. The device is simple in structure, and has the characteristics of high efficiency and self-adaption.

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.

The invention discloses a measurement method and system for multi-laser cooperative detection of nanobubbles, and belongs to the technical field of nanobubble measurement and detection. Through the excitation-detection double-laser system, key data such as the size, the service life and the formation threshold value of the nanobubbles are obtained in real time, the limitation of the traditional optical microscopic imaging resolution ratio is broken through, and the measurement precision is improved. Time-resolved imaging and thermal lens measurement are combined to realize omnibearing bubble monitoring. A time-resolved imaging technology is adopted to obtain information such as nucleation and collapse change of the nanobubbles. And in combination with thermal lens effect measurement, multi-angle measurement is realized. The generation of nano bubbles is accurately regulated and controlled, and laser processing and biological application are optimized. By adjusting parameters, controllable generation of nano bubbles is optimized, and the method is suitable for laser micromachining, microfluidic control, biomarking and other applications. In addition, the method is non-contact optical measurement, electrode or other external intervention is not needed, and the applicability is improved.

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 invention discloses a rod-like laser gain medium with radial concentration gradient distribution and a preparation method thereof, and belongs to the technical field of laser materials. Aiming at the thermal lens effect problem caused by Gaussian pump light in a high-power solid laser, the heat effect is inhibited through a material design source. Active ions of the gain medium are transition metal ions, a matrix material is a chalcogenide, the radial doping concentration of the gain medium is in high-low-high gradient distribution, Gaussian pump light intensity distribution is matched, and axis heat production is reduced. The preparation method comprises the steps of machining, transition metal film deposition, high-temperature diffusion and end face polishing. According to the design, the heat effect under high power is obviously inhibited, the light beam quality factor M2 is stabilized at 1.1-1.3, and the light-to-light conversion efficiency is obviously improved. The method is simple in process, low in cost and suitable for industrial production, and can be widely applied to the fields of high-power lasers, medical equipment, industrial processing and the like.

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.

In order to solve the problems existing in the existing high-power and high-energy femtosecond fiber amplification system, such as poor beam quality, low output energy, and high system integration complexity under the condition of high-power femtosecond output, the present invention provides a hybrid high-power and high-energy femtosecond chirped pulse amplification system and method. The amplification system and method of the present invention use a silicate glass fiber amplifier to form a pre-amplification system, cascade a single-crystal fiber with a single-pass structure as the main amplifier, abandon the use of an isolator based on a Faraday rotator, prevent the distortion of the beam quality caused by the thermal effect of the Faraday rotator crystal, self-assemble an isolator, and adopt a simple combination of independent devices of a polarization beam splitter prism and a quarter-wave plate, eliminating the thermal lens effect of the Faraday rotator and improving the beam quality. By using as few lenses as possible and a single-pass amplification structure, the optical path is simple, stable and reliable; by using aperture spatial filtering, a high beam quality output under a high power of more than 100 W is obtained.