Prof. Guangyong Jin Profile

KEYWORDS: Laser drilling, Aluminum, Pulsed laser operation, Numerical simulations, Laser processing, Interfaces, Optical simulations, Liquids, Laser energy, 3D modeling

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Proceedings Article | 15 October 2015 Paper

Thermal effects of single-pulse laser irradiation on fused silica

Ji-xing Cai, Xu Qu, He Li, Guang-yong Jin

Proceedings Volume 9671, 96711C (2015) https://doi.org/10.1117/12.2199892

KEYWORDS: Laser irradiation, Finite element methods, Thermal effects, Silica, Pulsed laser operation, Laser applications, Temperature metrology, Glasses, Laser energy, Analytical research

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Proceedings Article | 15 October 2015 Paper

Numerical simulation of temperature field and thermal stress field in silicon-based positive-intrinsic-negative photodiode irradiated by multipulsed millisecond laser

Guangyong Jin, Zhi Wei, Yong Tan, Hongyu Zhao

Proceedings Volume 9671, 96710R (2015) https://doi.org/10.1117/12.2199386

KEYWORDS: Silicon, Photodiodes, Semiconductor lasers, Laser irradiation, Thermal effects, Silica, Numerical simulations, Laser damage threshold, Laser applications, Thermal modeling

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Laser induced morphological damage have been observed in silicon-based positive-intrinsic-negative photodiode. This paper adopted the methods of the theoretical calculation and finite element numerical simulation to model, then solved the temperature field and thermal stress field in silicon-based positive-intrinsic-negative photodiode irradiated by multipulsed millisecond laser, and researched the features and laws of the temperature field and thermal stress field. As for the thermal-mechanical problem of multipulsed millisecond laser irradiating silicon-based positive-intrinsic-negative photodiode, based on Fourier heat conduction and thermoelasticity theories, we established a two-dimensional axisymmetric mathematical model .Then adopted finite element method to simulate the transient temperature field and thermal stress field. The temperature dependences of the material parameters and the absorption coefficient were taken into account in the calculation. The results indicated that there was the heat accumulation effect when multipulsed millisecond laser irradiating silicon-based positive-intrinsic-negative photodiode. The morphological damage threshold were obtained numerically. The evolution of temperature at the central point of the top surface, the temperature distribution along the radial direction in the end of laser irradiation and the temperature distribution along the axial direction in the end of laser irradiation were considered. Meanwhile, the radial stress, hoop stress, axial stress on the top surface and the R=500μm axis were also considered. The results showed that the morphological damage threshold decreased with the increased of the pulse number. The results of this study have reference significance of researching the thermal and thermal stress effect evolution’s features when multipulsed millisecond laser irradiating silicon-based positive-intrinsic-negative photodiode, then revealing the mechanism of interactions between millisecond laser and photodiode.

Proceedings Article | 15 October 2015 Paper

Experimental study on photodiode damage by millisecond pulse laser irradiation

Zhi Wei, Yong Tan, Di Wang, Guangyong Jin

Proceedings Volume 9671, 96710E (2015) https://doi.org/10.1117/12.2197826

KEYWORDS: PIN photodiodes, Silicon, Laser irradiation, Laser energy, Semiconductor lasers, Sensors, Photodiodes, Pulsed laser operation, Laser ablation, Laser applications

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The photoelectric detector is a very significance part in laser and its application system, but when photoelectric detector irradiated by high energy laser, the laser may cause thermal damage to the photoelectric detector, when the temperature more than its melting point and vaporization point, there will be a permanent damage in PIN photodetector, leading to the failure of photoelectric detector. In order to study the photodiode damage mechanism by millisecond pulse laser irradiation, a set of experimental system has been built, choosing appropriate pulsed laser parameters to irradiate silicon-based PIN photodiode and monitoring the surface temperature in the process of irradiation, until the PIN photodiode complete failure. The measurement results of real-time temperature, responsivity change and damage morphology were analyzed to conclude the failure reason of the PIN photodiode. The results showed that with the increase of laser energy, the PIN photodiode surface temperature would be also increased accordingly. Before the laser irradiation, the responsivity of PIN photodiode was the same. But after the laser irradiation, the responsivity of the PIN photodiode would be changed and with the increase of laser energy, the decline extent of responsivity would be also increased. Judging from the ablation, crack and fold zone on the surface of PIN photodiode after the laser irradiation, the damage was for thermal stress effect. The continuity of material confined its free expansion. Therefore, the uneven thermal expansion induced the great thermal stress. At the same time, the silicon transited from brittle to ductile and the yield strength dramatically decreased. Once the maximum thermal stress exceeded the critical stress, the plastic deformation and the brittle cracks of silicon would be generated. With the increase of laser energy, the thermal stress damage extent of PIN photodiode would be also increased accordingly and the black area of laser ablation would be also larger. In this paper, the damage mechanism of silicon-based PIN photodiode irradiated by millisecond pulse laser is that the thermal stress causes the phenomena of ablation, fold and responsivity change. The conclusions have a vital significance in improving the performance of PIN photodiode in the field of laser application.

Proceedings Article | 4 March 2015 Paper

Numerical simulation of different pulse width of long pulsed laser on aluminum alloy

Mingxin Li, Guangyong Jin, Juan Bi, Wei Zhang, Gui-bo Chen

Proceedings Volume 9521, 95211P (2015) https://doi.org/10.1117/12.2182144

KEYWORDS: Aluminum, Pulsed laser operation, Data modeling, Interfaces, Optical simulations, Laser drilling, Numerical simulations, Laser processing, Liquids, Data centers

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Proceedings Article | 4 March 2015 Paper

Numerical simulation of different pulse width of long pulsed laser on aluminum alloy

Guangyong Jin, Mingxin Li, Wei Zhang, Guibo Chen, Juan Bi

Proceedings Volume 9521, 95211R (2015) https://doi.org/10.1117/12.2182358

KEYWORDS: Aluminum, Pulsed laser operation, Data modeling, Interfaces, Optical simulations, Laser drilling, Numerical simulations, Laser processing, Liquids, Data centers

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Proceedings Article | 18 December 2014 Paper

Theoretical simulation of melt ejection during the laser drilling process on aluminum alloy by single pulsed laser

Mingxin Li, Ming Guo, Di Wang, Xiuying Gu, Guangyong Jin

Proceedings Volume 9295, 92950Q (2014) https://doi.org/10.1117/12.2072886

KEYWORDS: Aluminum, Optical simulations, Interfaces, Pulsed laser operation, Laser drilling, Laser processing, Data modeling, Liquids, Thermal modeling, Data centers

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Proceedings Article | 18 December 2014 Paper

Widely tunable mid-infrared optical parametric oscillator based on a multiple periods MgO:PPLN

Yong-ji Yu, Rui-zhi Zhai, Jing Zhao, Xin-yu Chen, Chao Wang, Chun-ting Wu, Guang-yong Jin

Proceedings Volume 9295, 92950W (2014) https://doi.org/10.1117/12.2073102

KEYWORDS: Optical parametric oscillators, Crystals, Mid-IR, Laser crystals, Temperature metrology, Semiconductor lasers, Acousto-optics, Neodymium lasers, Pulsed laser operation, Tunable lasers

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Proceedings Article | 18 December 2014 Paper

Temperature and thermal stress fields during the pulse train of long-pulse laser irradiating aluminium alloy plate

Guangyong Jin, Xiu-ying Gu, Wei Zhang

Proceedings Volume 9295, 92950K (2014) https://doi.org/10.1117/12.2072857

KEYWORDS: Aluminum, Pulsed laser operation, Laser applications, Laser irradiation, Finite element methods, Laser energy, Metals, Thermal modeling, Diffusion, Absorption

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Proceedings Article | 18 December 2014 Paper

Research on the thermal effect of copper between adjacent pulses under moving laser irradiation

Boshi Yuan, Di Wang, Guangyong Jin, Zhi Wei, HuaDong Yu

Proceedings Volume 9295, 92950M (2014) https://doi.org/10.1117/12.2072862

KEYWORDS: Copper, Pulsed laser operation, Laser irradiation, Thermal effects, Copper vapor lasers, Optical simulations, Metals, Laser applications, Optimization (mathematics), Finite element methods

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Proceedings Article | 18 December 2014 Paper

Thermal stress simulation of multi-pulse laser irradiate on fused silica

Ji-xing Cai, Ming Guo, Guang-yong Jin, Hua-dong Yu

Proceedings Volume 9295, 92950O (2014) https://doi.org/10.1117/12.2072872

KEYWORDS: Silica, Pulsed laser operation, Optical simulations, Finite element methods, Laser processing, Temperature metrology, Laser applications, Laser energy, Distortion, Numerical simulations

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Proceedings Article | 18 December 2014 Paper

High-repetition-rate and short pulse-width 1064-nm laser in a composite crystal device

Zijian Wang, Yongji Yu, Ruizhi Zhai, Guangyong Jin

Proceedings Volume 9295, 92950L (2014) https://doi.org/10.1117/12.2072861

KEYWORDS: Crystals, Laser crystals, Composites, Laser countermeasures, Q switched lasers, Mirrors, Pulsed laser operation, Q switching, Neodymium lasers, Absorption

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Proceedings Article | 18 December 2014 Paper

Numerical analysis of thermal effect in aluminum alloy by monopulse laser

Xiuying Gu, Guibo Chen, Wei Zhang, Mingxin Li, Guangyong Jin

Proceedings Volume 9295, 92950N (2014) https://doi.org/10.1117/12.2072868

KEYWORDS: Aluminum, Pulsed laser operation, Absorption, Temperature metrology, Thermal effects, Numerical simulations, Laser energy, Numerical analysis, Finite element methods, Laser processing

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A spatial axisymmetric finite element model is established to investigate the distribution characteristics of temperature field that monopulse millisecond laser act on aluminum alloy. The thermal process of laser acting on aluminum alloy (melting, gasification and temperature drop) is simulated. Using the specific quivalent heat capacity method to simulate the solid-liquid, liquid-gas phase transition of aluminum alloy, and considering the differences of thermal physical parameters between different states (solid-liquid, liquid-gas) of aluminum alloy in the process of numerical simulation. The distribution of temperature field of aluminum alloy caused by the change of energy density, pulse width and spot radius of monopulse millisecond laser are investigated systematically by using numerical simulation model. The numerical results show that the temperature of target no longer rises after reaching the target gasification. Given the pulse width and spot radius, the temperature of target rise as the energy density increases, the laser intensity distribution is gaussian, so the temperature distribution of the target surface also shows Gaussian. The energy absorption mechanism of aluminum alloy is surface absorption mechanism, the temperature gradient in axial of the target is much lager than the temperature gradient in radial of the target surface, so the temperature rise in axial only exists a thin layer of target surface. Given the energy density and spot radius, as the pulse width increases, the power density of laser decreases, therefore the temperature of target center point decreases as the pulse width increases, and the temperature difference becomes small. As the pulse width decreases, the heat transfer in axial reduce, the deposition of energy enhances on the surface. Given the energy density and pulse width, the distribution of the temperature is enlarged as the spot radius increases, but the distribution of the temperature in axial is independent of the spot radius.

Proceedings Article | 18 December 2014 Paper

Numerical simulation for influence of pulse width on the temperature field of unidirectional carbon fiber

Boshi Yuan, Zhi Wei, Di Wang, Yao Ma, Guangyong Jin

Proceedings Volume 9295, 92950P (2014) https://doi.org/10.1117/12.2072885

KEYWORDS: Carbon, Fiber lasers, Pulsed laser operation, Laser energy, 3D modeling, Laser irradiation, Temperature metrology, Composites, Anisotropy, Numerical simulations

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The unidirectional carbon fiber material is commonly used in the Carbon Fiber Reinforced Plastics (CFRP). The COMSOL Multiphysics finite element analysis software was utilized in this paper. And the 3D anisotropy model, which based on heat conduction equation, was established to simulate the temperature field of the carbon fiber irradiated by pulse laser. The research focused on the influences of the laser width on the material temperature field. The thermal analysis results indicated that during the process of irradiation, the temperature field distribution of the carbon fiber was different from the distribution of laser spot on the surface. The incident laser is Gauss laser, but the temperature field distribution presented oval. It resulted from the heat transfer coefficient of carbon fiber was different in the axial and in the radial. The temperature passed along the fiber axial faster than the radial. Under the condition of the laser energy density constant, and during the laser irradiation time, the depth of the carbon fiber temperature field increased with the pulse width increasing, and the area of the carbon fiber temperature field increased with the pulse width increasing, However, the temperature of the laser irradiated center showed a trend of decrease with the increasing of pulse width. The results showed that when the laser affection was constant, the laser energy affected on the carbon fiber per unit time was increased with the decrease of the pulse width. Due to the limits of the heat transfer coefficient of the material and laser irradiation time, the energy was injected in carbon fiber within a short time. With the reducing of the heat conduction area, the depth and the area of the temperature field would be also decreased. With the increase of pulse width, the time of energy injected in carbon fiber was increased, and the laser energy affected on the carbon fiber per unit time was decrease. With the heat conduction area increasing, the depth and area of the temperature field would be also increased. In this paper, the rule of the temperature field changing with the pulse width was consistent with the law of conservation of energy and the heat conduction.

Proceedings Article | 18 December 2014 Paper

Study and design of beam expander with wide aperture

Guangyong Jin, Ming Guo, Jixing Cai, Wei Zhang, Zhi Wei

Proceedings Volume 9295, 92950T (2014) https://doi.org/10.1117/12.2073035

KEYWORDS: Beam expanders, Laser systems engineering, Image quality standards, Objectives, Laser applications, Collimation, Zemax, Image quality, Laser processing, 3D modeling

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In order to improve the capacity of beam collimation for laser beam expander, it is necessary to design a more reasonable and feasible structure of beam expander system. Laser beam expander is used to compress the laser divergence angle, in order to reduce the energy losing in long distance scanning acquisition system. This paper introduces the working principle and design idea of the laser beam expander, the collimating multiplying power focal length and the collimated magnification formula of expander main, secondary mirror. According to the third-order aberration theory, Considering the spherical aberration, sine difference and divergence angle, the reasonable analysis of optical path, ZEMAX optical design software was used to design large-diameter laser beam expander and analysis and optimize, And given the actual design data and results. Display the maximum optical path difference is ±0.01λ of the main light ray and each light ray. To combination the rear- group objective lens of Galileo and Kepler beam expander, a large-diameter(1.475m) laser beam expander was designed with 0.2m in the diameter, 1/2m in the relative caliber. In the objective lens System, a high-order aspherical was used to the aberration of extra-axial point. we can see that the image quality is close to the diffraction limit from the curves of wavefront. In addition to improve image quality effectively, the system has the characteristics of simple structure, less costly and less design difficulty to compare with the other beam expanding system. And make the output beam's divergence angle smaller, energy density higher, and the beam quality has been greatly improved. The results show that the beam expander is fully meet the design requirements, the use effect is good. Design and research of laser beam expanding system not only improves the quality of the laser beam in the laser system, but also enlarge the application field of laser technology in photoelectric system.

Proceedings Article | 18 December 2014 Paper

Study on temperature distribution characteristics of alumina irradiating by irregular laser

Guangyong Jin, Di Wang, Zhi Wei, Boshi Yuan, Chuanhui Fan

Proceedings Volume 9295, 92950U (2014) https://doi.org/10.1117/12.2073038

KEYWORDS: Pulsed laser operation, Laser irradiation, Laser energy, Laser processing, Wavefront distortions, Numerical simulations, Energy transfer, Laser applications, Laser beam propagation, Fluctuations and noise

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Proceedings Article | 18 December 2014 Paper

Analysis of thermodynamic effect in Si irradiated by pulsed-laser

Huadong Yu, Ming Guo, Guangyong Jin, Mingxin Li, Yao Ma, Boshi Yuan

Proceedings Volume 9295, 92950S (2014) https://doi.org/10.1117/12.2073029

KEYWORDS: Silicon, Semiconductor lasers, Pulsed laser operation, Laser energy, 3D modeling, Laser irradiation, Temperature metrology, Laser applications, Thermal effects, Thermodynamics

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According to the heat conduction equation, thermoelastic equation and boundary conditions of finite, using the finite element method(FEM), established the three-dimensional finite element calculation model of thermal elastic ,numerical simulation the transient temperature field and stress field distribution of the single crystal silicon materials by the pulsing laser irradiation, and analytic solution the temperature distribution and stress distribution of laser irradiation on the silicon material , and analyzes the different parameters such as laser energy, pulse width, pulse number influence on temperature and stress, and the intrinsic damage mechanism of pulsed laser irradiation on silicon were studied. The results show that the silicon material is mainly in hot melt under the action of ablation damage.According to the irradiation of different energy and different pulse laser ,we can obtain the center temperature distribution, then get the law of the change of temperature with the variation of laser energy and pulse width in silicon material; according to the principal stress and shear stress distribution in 110 direction with different energy and different pulse, we can get the law of the change of stress distribution with the variation of laser energy and pulse width ;according to the principal stress distribution of single pulse and pulse train in 110 direction, we can get the law of the change of stress with pulse numbers in silicon.When power density of laser on optical material surface (or energy density) is the damage threshold, the optical material surface will form a spontaneous, periodic, and permanent surface ripple, it is called periodic surface structure laser induced (LIPSS).It is the condensed optical field of work to generate low dimensional quantum structures by laser irradiation on Si samples. The pioneering work of research and development and application of low dimensional quantum system has important academic value.The result of this paper provides theoretical foundation not only for research of theories of Si and substrate thermal stress damage and its numerical simulation under laser radiation but also for pulse laser technology and widening its application scope.

Proceedings Article | 9 December 2014 Paper

Investigation on the influence of BBO thermal-induced phase mismatching in 266-nm UV laser conversion efficiency

Guangyong Jin, Kai Yu, Miao Yu, Zhulong Huang, Ruizhi Zhai, Lei Wang

Proceedings Volume 9294, 92940Q (2014) https://doi.org/10.1117/12.2072884

KEYWORDS: Crystals, Laser crystals, Ultraviolet radiation, Nonlinear crystals, Temperature metrology, Second-harmonic generation, High power lasers, Laser applications, Laser processing, Optical simulations

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266nm UV laser has a wide range of applications in many fields, such as laser medical treatment, laser processing, precision measure and other applications for the reason of its advantages in wavelength, small diffraction effects, high single-photon energy, and high resolution and so on. BBO crystals absorb parts of the fundamental laser energy and second harmonic laser energy are unavoidable, and thus the temperature raise, so that the existing crystal phase matching conditions change, resulting in phase mismatching in the high-power frequency doubling, greatly influence the 266nm UV laser conversion efficiency. To further study the effect of phase mismatching to conversion efficiency, and improve the conversion efficiency, output power and other output characteristics of 266nm laser, the article mainly describe from the following three aspects. Firstly, took the use of three-dimensional nonlinear crystal temperature distribution which is obtained, the process of BBO crystal thermal-induced phase mismatching is analyzed. Secondly, based on frequency doubling theory, the effects of the thermal-induced phase mismatching affected of conversion in crystals are analyzed. Combining with the phase mismatching of the three-dimensional distributions, the fourth harmonic conversion efficiency with thermal phase mismatching changes of BBO 266nm UV laser are simulated for the first time. Thirdly, by using MATLAB software, the effects of phase mismatching to conversion efficiency in crystal for different waist radius, 532nm laser power and the fundamental beam quality are simulated. The results indicate a good physical interpretation of reasons of high power laser frequency doubling system. It shows that the model established explains the reason of the reduction of conversion efficiency, output power and the beam quality excellently. All results make a leading sense to the research on the compensating of the phase mismatching and on the improvement of conversion efficiency.

Proceedings Article | 18 November 2014 Paper

Analysis on the thermal effect of dual-end pumped Tm:YLF crystal

Zhu-long Huang, Guang-yong Jin, Xin-yu Chen, Chun-ting Wu, Lei Wang

Proceedings Volume 9298, 92981N (2014) https://doi.org/10.1117/12.2072853

KEYWORDS: Crystals, Thermal effects, Laser crystals, Doping, Thermal modeling, Thulium, Distortion, Absorption, MATLAB, Refractive index

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Proceedings Article | 18 November 2014 Paper

Pump couplers in a series connection

Guangyong Jin, Qirong Xiao, Ping Yan, Mali Gong, Xiao Chen

Proceedings Volume 9266, 92661I (2014) https://doi.org/10.1117/12.2074419

KEYWORDS: Optical pumping, Optical fibers, Signal attenuation, Fiber lasers, Laser systems engineering, Fluorine, Laser applications, High power lasers, Fusion splicing, Manufacturing

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SPIE Journal Paper | 2 December 2013

High-repetition-rate tunable mid-infrared optical parametric oscillator based on MgO: periodically poled lithium niobate

Yongji Yu, Xinyu Chen, Jing Zhao, Chao Wang, Chunting Wu, Guangyong Jin

OE, Vol. 53, Issue 06, 061604, (December 2013) https://doi.org/10.1117/12.10.1117/1.OE.53.6.061604

KEYWORDS: Optical parametric oscillators, Crystals, Mid-IR, Neodymium, Lithium niobate, Q switched lasers, Q switching, Mirrors, Electro optics, Reflectivity

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Proceedings Article | 17 September 2013 Paper

Numerical study of thermal stress damage in dielectric film by long-pulse laser

Ji-xing Cai, Guang-yong Jin, Juan Bi, Gui-bo Chen, Ye Zhang

Proceedings Volume 8904, 89040M (2013) https://doi.org/10.1117/12.2032890

KEYWORDS: Dielectrics, Laser energy, Laser irradiation, Thin films, Laser applications, Optical simulations, Pulsed laser operation, Absorption, Thermal modeling, Systems modeling

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In this paper, we study and establish the theoretical model of thermal stress damage of dielectric film in film/substrate systems caused by long-pulse laser, based on which transient distributions of temperature field and thermal stress field are simulated using the finite element method(FEM) and then analyze the mechanism of the damage. In accordance with the basic equation of heat conduction equation and thermal stress equation, the physical model of dielectric film and the substrate transient temperature field and thermal stress field is developed with the assumption that the dielectric film and the substrate are isotropic and their thermal parameters do not change with temperature. On the foundation of theoretical analysis, transient of temperature field in dielectric film in film/substrate systems under long-pulse laser irradiation is simulated and calculated. The numerical results indicate that great temperature gradient exists in dielectric film and substrate in radial direction but smaller one exists in axial direction. When the laser power density is increasingly larger, the temperature gradient in radial direction is larger and the temperature in the center of the film is higher. Transient thermal stress field in dielectric film in film/substrate systems under long-pulse laser irradiation is simulated. Numerical results show that, the damage to the dielectric film caused by long-pulse laser is mainly due to thermal stress damage process which circumferential stress acts a primary role in. Such damage is a final result of the substrate being under thermal stress. For film/substrate system, the damage under long-pulse laser radiation starts from the substrate. When the laser power density is increasingly larger, the dielectric film is more vulnerable to damage and damage zone is greater. The result of this paper provides theoretical foundation not only for research of theories of dielectric film and substrate thermal stress damage and its numerical simulation under laser radiation but also for long-pulse laser technology and widening its application scope.

Proceedings Article | 17 September 2013 Paper

Thermal effect in pulsed laser diode dual-end pumped Tm:YAG laser

Guang-yong Jin, Jing Wu, Chun-ting Wu, Er-he Fan, Chao Wang, Xin-yu Chen, Yong-ji Yu

Proceedings Volume 8904, 890413 (2013) https://doi.org/10.1117/12.2034333

KEYWORDS: Crystals, Semiconductor lasers, Rod lasers, Thermal effects, Pulsed laser operation, Laser crystals, Integral transforms, Laser applications, Absorption, Refractive index

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Based on the actual working environment of pulse LD dual-end pumped Tm:YAG crystal, time-dependent temperature field analytical expression and the time-varying thermal focal length are deduced by the integral transform method. Additionally, the effects of pump power, repetition frequency and duty ratio on axial transient temperature distribution and time-varying thermal focal length of pulse LD dual-end pumped Tm:YAG rod are simulated and analyzed. The results show that the temperature distribution reaches steady state respectively by 11, 14, 15 pulses under pump power of 30W, 35W and 40W, respectively, while the frequency is 100Hz and the duty ratio is 50%. Under the condition mentioned above, the temperature of the crystal rod on both ends of the center arrives 34.7°C, 37.5°C, 40.3°C, which is 1.8°C, 2.1°C, 2.4°C higher than the center of rod. And the thermal focal length is in the range of 31.5-41.5cm, 26.5-34.6cm, 22.9-29.7cm, respectively. When pump energy is 100mJ, frequency at 110Hz, 120 Hz, 130Hz and duty ratio at 55%, 60%, 65%, respectively, the temperature distribution reaches steady state respectively by 13, 15, 16 pulses, and the temperature of the rod on both ends of the center respectively arrives 30.0°C, 30.9°C, 31.8°C, which is 1.3°C, 1.4°C, 1.5°C higher than the center of rod, and thermal focal length is in the range 46.4-58.8cm, 42.7-51.6cm, 39.5-45.9cm, respectively. Namely, as the increase of the pulses number, the distribution of the temperature and the thermal focal length in crystal rod appear jagged and eventually get to the periodic distributions. With the increase of the pump power, repetition frequency and duty ratio, the temperature difference between the crystal rod on both ends of the center and the center of rod is increasing, while time-varying thermal focal length gradually becomes shorter and the fluctuation range is smaller until it reaches steady state. The results provide theoretical basis for heating compensation and cavity design of pulsed thulium doped lasers.

Proceedings Article | 17 September 2013 Paper

Influence of BBO temperature distribution on phase mismatching distribution in fourth harmonic

Chao Wang, Miao Yu, Xin-yu Chen, Xue-chun Tan, Yong-ji Yu, Guang-yong Jin, Chun-ming Wan

Proceedings Volume 8904, 890414 (2013) https://doi.org/10.1117/12.2034339

KEYWORDS: Crystals, Laser crystals, Nonlinear crystals, Second-harmonic generation, High power lasers, 3D modeling, Temperature metrology, Ultraviolet radiation, Mathematical modeling, Thermal modeling

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266nm UV laser has a wide range of applications in various fields by its advantages in high single photon energy and high resolution, which also has a development gradually moving in the direction of high power and high conversion efficiency. In the process of high-power laser frequency doubling, BBO crystal inevitably absorbs part of fundamental light power and frequency doubled light power, it induced the temperature rise along the direction of radiation in crystal and destroyed the phase-matching conditions of BBO crystal that lead to phase mismatching. In order to improve harmonic conversion efficiency as well as reduce the influence of output power and beam quality caused by phase mismatching, in this paper we analyzed the process of phase mismatching, established the thermal-induced phase mismatching model by using analytical expression of the nonlinear crystal temperature field equation which has been given, and the three-dimensional phase mismatching distribution were obtained. There are three major contributions in the paper. Firstly, the working process of the nonlinear crystal was analyzed, and the physical and mathematical models of temperature distributions were established, and the BBO crystal three-dimensional temperature distributions were also obtained. Secondly, a variety of factors that affect the temperature distributions within the BBO crystal were summarized. For different 532nm waist radius and 532nm input power, they were numerical simulated use of MATLAB. Finally, combined with the above analysis, the physical and mathematical models of phase mismatching caused by energy absorption of BBO in forth harmonics generation were established, the phase mismatching distributions in the crystal were simulated as well, especially the changes to phase mismatching distributions with different parameter were analyzed. Combination of the multiplier theory, the influence of phase mismatching on frequency doubling conversion efficiency was analyzed. The results indicate that the physical model which established in this paper can explain the physical reasons in high-power laser frequency doubling system very well, such as the reduce in conversion efficiency and output power and beam quality. All research results play instructive effect at the improvement of conversion efficiency and the compensation for the phase mismatching for further research.

Proceedings Article | 17 September 2013 Paper

Research on output characteristics of continuous-wave operation of Ho:YAG laser pumped by Tm:YLF laser

Xinyu Chen, Jiaqi Bie, Zhulong Huang, Xuedi Song, Guangyong Jin

Proceedings Volume 8904, 890419 (2013) https://doi.org/10.1117/12.2034596

KEYWORDS: Holmium, Upconversion, Laser damage threshold, Laser crystals, Crystals, Thulium, Mirrors, Reflectivity, Continuous wave operation, YAG lasers

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Proceedings Article | 17 September 2013 Paper

86 W continuous-wave diode side-pumped 1341.4nm Nd:YAP laser

Yong-ji Yu, Jing Zhao, Xin-yu Chen, Chao Wang, Chun-ting Wu, Guang-yong Jin

Proceedings Volume 8904, 89041O (2013) https://doi.org/10.1117/12.2035107

KEYWORDS: Crystals, Semiconductor lasers, Continuous wave operation, Laser crystals, Diodes, High power lasers, Mirrors, Laser applications, Neodymium lasers, Resonators

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Proceedings Article | 17 September 2013 Paper

LD dual-end-pumped CW Tm:YLF laser

Xin-yu Chen, Yu Zhang, Yong-ji Yu, Chao Wang, Guang-yong Jin

Proceedings Volume 8904, 890417 (2013) https://doi.org/10.1117/12.2034533

KEYWORDS: Continuous wave operation, Resonators, Crystals, Mirrors, Thulium, Laser crystals, Ions, Laser damage threshold, Upconversion, Thermal effects

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We report on a LD dual-end-pumped 792nm continuous wave operation Tm:YLF laser. Firstly, the rate equation of LD end-pumped CW operation Tm:YLF laser were established, in which the energy transfer upconversion and without energy transfer upconversion under continuous-wave considerate were considered, as well the pump threshold and the slope efficiency of the laser system were analyzed. Simultaneously, the cavity stability condition and the pattern matching of the plano- concave resonator were analyzed according to ABCD Matrix theory. Comparing respectively the laser threshold and the slope efficiency and optical-optical conversion efficiency under circumstances which the output mirror transmittance of 15% and 23%. In addition, the M2 of the output laser were contrasted and analyzed in adjusting the resonator cavity length by using different radius of curvature of the output mirror in 150mm, 200mm and 300mm all in the above case. As the process of thermal lens focal length changing greater than 90mm, it exhibited that the two fundamental modes in the cavity resonator matched well in numerical simulation when the radius of curvature of the output mirror was 300mm, as well the two fundamental modes matched well when it more than 100mm in a certain pump power. We designed a single LD dual-end-pumped continuous wave operation Tm:YLF laser. Using Tm:YLF (3 at.%) crystal for gain medium, which the size was 3×3×14mm³. In experiments, the Tm:YLF laser crystal keeps 291K and the temperature control method is water cooling. The length of the resonator was 135mm when L shape plano-concave resonator was applied, and the radius of curvature output mirror was 300mm, as well as the temperature of the Tm:YLF laser crystal was 291K. The output laser we observed by this system and the central laser wavelength was 1944nm. The threshold power was 8.11W and the highest output power reaches to 4.01W when the totally input pump power was 17W, and the optical conversion efficiency was 23.6%. The far-field divergence angle was 3.8mrad after calculation. Respectively. The experimental results are coinciding with the theory.

Proceedings Article | 16 May 2013 Paper

Characteristics of shock wave from nanosecond laser-produced aluminum plasma in air

Jingquan Lin, Xun Gao, Zehao Liu, Changkai Sun, Zuoqiang Hao, Guangyong Jin, Tianhang Liu

Proceedings Volume 8796, 879611 (2013) https://doi.org/10.1117/12.2010620

KEYWORDS: Plasma, Aluminum, Laser energy, Pulsed laser operation, Laser applications, Wavefronts, Plasma generation, CCD cameras, Laser ablation, Laser beam diagnostics

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Proceedings Article | 5 August 2009 Paper

Method of partial vision temperature measurement by infrared thermometer

Xiao-guang Shi, Ke-wei Huan, Chao Wang, Guang-yong Jin

Proceedings Volume 7383, 738304 (2009) https://doi.org/10.1117/12.835254

KEYWORDS: Temperature metrology, Infrared radiation, Thermometry, Thermography, Target detection, Black bodies, Sensors, Infrared detectors, Distance measurement, Error analysis

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Proceedings Article | 12 September 2002 Paper

Research on a medical noncontact blood-sampling laser instrument

Zhu Liang, Zhong Ren, Guicai Song, Xiaoyuan Yan, Guangyong Jin, Guobin Ning

Proceedings Volume 4916, (2002) https://doi.org/10.1117/12.482953

KEYWORDS: Blood, Tissues, Erbium lasers, Erbium, YAG lasers, Medical research, Skin, Absorption, Laser development, Laser systems engineering

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Proceedings Article | 5 September 2002 Paper

Temperature characteristics of Nd:YAG bar pumped by high-repetition-rate LD

Zhong Ren, Xiaoyuan Yan, Guicai Song, Zhu Liang, Guobin Ning, Guangyong Jin

Proceedings Volume 4913, (2002) https://doi.org/10.1117/12.482240

KEYWORDS: Rod lasers, Refractive index, Nd:YAG lasers, Birefringence, Thermal effects, Photoelasticity, Crystals, Polarization, Laser optics, Crystal optics

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Proceedings Article | 5 September 2002 Paper

Frequency-doubling technique of serial pulse Nd:YAG laser

Guangyong Jin, Zhu Liang, Xiaoyuan Yan, Guicai Song, Zhong Ren, Guobin Ning

Proceedings Volume 4914, (2002) https://doi.org/10.1117/12.481757

KEYWORDS: Pulsed laser operation, Nd:YAG lasers, Electro optics, Lamps, Modulation, Luminescence, Laser applications, Q switched lasers, Q switching, Second-harmonic generation

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Proceedings Article | 5 September 2002 Paper

Research on quasi-continuous narrow-burst laser fiber refraction coupler

Xiaoyuan Yan, Guicai Song, Guangyong Jin, Zhong Ren, Guobin Ning, Zhu Liang

Proceedings Volume 4914, (2002) https://doi.org/10.1117/12.481836

KEYWORDS: Fiber couplers, Fiber lasers, Fiber coupled lasers, Light sources, Light, Pulsed laser operation, Laser applications, Refraction, Ray tracing, Gaussian beams

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Proceedings Article | 5 September 2002 Paper

Q-cw array LD-pumped Nd:YAG laser

Guobin Ning, Guangyong Jin, Zhong Ren, Guicai Song, Zhu Ling, Xiaoyuan Yan

Proceedings Volume 4914, (2002) https://doi.org/10.1117/12.481837

KEYWORDS: Neodymium, Nd:YAG lasers, YAG lasers, Crystals, Q switching, Electro optical modeling, Pulsed laser operation, Rod lasers, Wave plates, Q switched lasers

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Proceedings Article | 5 September 2002 Paper

Wide-pulse Nd:YAG high-repetition-frequency Q-switch technique

Guicai Song, Guangyong Jin, Zhu Liang, Xiaoyuan Yan, Zhong Ren, Guobin Ning

Proceedings Volume 4914, (2002) https://doi.org/10.1117/12.481752

KEYWORDS: Pulsed laser operation, Neodymium, Q switching, Lamps, Nd:YAG lasers, Q switched lasers, Resonators, YAG lasers, Electro optics, Mirrors

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Showing 5 of 39 publications

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