Calculation of Absorption Rate of Optical Elements Based on Temperature Field
Zhu Ye, Wang Chen, Zhang Chong, and Guo Chongyang
The optical absorption loss of optical thin films can be assessed through the temperature field generated at the spot following laser irradiation. An experimental platform is established to measure the temperature field of the element under laser irradiation. Numerical calculations are employed to simulate the transient laser heating process based on the observed temperature field. Subsequently, the material absorptivity is determined by comparing the simulated transient process with the experimental temperature field. The results show that the laser power density is the main factor affecting the temperature rise, and the temperature graduation is also affected by the convective heat flux, which is 15 W/ (m2·K) according to the experimental cooling process. The temperature field simulation shows that the absorptivity of the high negative laser is 3.2×10-6. An increase in laser power results in consistent temperature rise trends and magnitudes for optical components, validating the accuracy of the laser irradiation model and presenting a novel method for calculating the absorption rates of various optical components.The optical absorption loss of optical thin films can be assessed through the temperature field generated at the spot following laser irradiation. An experimental platform is established to measure the temperature field of the element under laser irradiation. Numerical calculations are employed to simulate the transient laser heating process based on the observed temperature field. Subsequently, the material absorptivity is determined by comparing the simulated transient process with the experimental temperature field. The results show that the laser power density is the main factor affecting the temperature rise, and the temperature graduation is also affected by the convective heat flux, which is 15 W/ (m2·K) according to the experimental cooling process. The temperature field simulation shows that the absorptivity of the high negative laser is 3.2×10-6. An increase in laser power results in consistent temperature rise trends and magnitudes for optical components, validating the accuracy of the laser irradiation model and presenting a novel method for calculating the absorption rates of various optical components.
- Dec. 17, 2025
- APPLIED LASER
- Vol. 45, Issue 10, 205 (2025)
- DOI：10.14128/j.cnki.al.20254510.205
Design of a 150 mm Diameter Atmospheric Turbulence Simulation System
He Guoqiang, Yu Xin, Bai Suping, Liu Cai, Wang Jiahao, and Han Jiahao
The rapid development of large-aperture star sensors to meet the demand for detecting extreme stars cannot be ignored. However, it is important to consider the impact of atmospheric turbulence on star sensors during stargazing tests conducted on the ground. Therefore, in this paper, the design of a turbulence simulator with an aperture of 150 mm is carried out to meet the needs of a star sensor. Firstly, limited by the liquid crystal size of the turbulence simulation device, based on the initial structure of the Kepler telescope, a large magnification beam expansion scheme is used to achieve the simulation of large aperture turbulence. Second, combined with the principle of conjugate imaging, the simulated turbulence information is mapped to the pupil surface position by constructing a conjugate surface. In addition, the method of sparse spectral model is used to simulate the atmospheric turbulence. Finally, an experimental platform is constructed to verify the design results. The experimental results show that the optical system obtains the output of a star point containing 150 mm of turbulence information under the conditions of conjugate imaging and pupil matching, and the atmospheric coherence length is 1~15 cm.The rapid development of large-aperture star sensors to meet the demand for detecting extreme stars cannot be ignored. However, it is important to consider the impact of atmospheric turbulence on star sensors during stargazing tests conducted on the ground. Therefore, in this paper, the design of a turbulence simulator with an aperture of 150 mm is carried out to meet the needs of a star sensor. Firstly, limited by the liquid crystal size of the turbulence simulation device, based on the initial structure of the Kepler telescope, a large magnification beam expansion scheme is used to achieve the simulation of large aperture turbulence. Second, combined with the principle of conjugate imaging, the simulated turbulence information is mapped to the pupil surface position by constructing a conjugate surface. In addition, the method of sparse spectral model is used to simulate the atmospheric turbulence. Finally, an experimental platform is constructed to verify the design results. The experimental results show that the optical system obtains the output of a star point containing 150 mm of turbulence information under the conditions of conjugate imaging and pupil matching, and the atmospheric coherence length is 1~15 cm.
- Dec. 17, 2025
- APPLIED LASER
- Vol. 45, Issue 10, 191 (2025)
- DOI：10.14128/j.cnki.al.20254510.191
Alignment Method for Polarization Maintaining Fiber Based on Side-Lobe Light Intensity
Guo Na, Wang Dongbo, Yi Yongqing, and Chen Liqiang
Panda type polarization maintaining fiber has strong polarization maintaining ability and is widely used in fields such as interferometric sensing and coherent optical communication. Determining the polarization axis of the panda-type polarization maintaining fiber is of great significance to improve the accuracy of related devices. This article is based on the side imaging of polarization maintaining fibers. Through theoretical simulation, it was found that when the polarization azimuth angle is around 90°,the intensity distribution curve shows a five finger shape, and the changes in sidelobe intensity are the most sensitive. Propose to use the characteristic values of the five finger sidelobes to determine the polarization axis of panda shaped polarization maintaining fibers. This method has fewer data collection points, faster axis measurement speed, and an experimental axis measurement accuracy of 0.5°.Panda type polarization maintaining fiber has strong polarization maintaining ability and is widely used in fields such as interferometric sensing and coherent optical communication. Determining the polarization axis of the panda-type polarization maintaining fiber is of great significance to improve the accuracy of related devices. This article is based on the side imaging of polarization maintaining fibers. Through theoretical simulation, it was found that when the polarization azimuth angle is around 90°,the intensity distribution curve shows a five finger shape, and the changes in sidelobe intensity are the most sensitive. Propose to use the characteristic values of the five finger sidelobes to determine the polarization axis of panda shaped polarization maintaining fibers. This method has fewer data collection points, faster axis measurement speed, and an experimental axis measurement accuracy of 0.5°.
- Dec. 17, 2025
- APPLIED LASER
- Vol. 45, Issue 10, 186 (2025)
- DOI：10.14128/j.cnki.al.20254510.186
Research on Segmentation and Registration of Roof Point Cloud Without Prior Pose Information
Zhou Hangyu, Wu Guanhong and Wang Cheng
Aiming at the airborne LiDAR point cloud data of building roofs lacking prior pose information, this paper proposes a registration method that combines roof surface segmentation and the improved four-point consistent set(4PCS) algorithm. Firstly, the roof surface of the source and target point cloud is extracted based on a roof seed point. Next, the similarity between patches of the source point cloud and the roof surface point cloud in the target point cloud is calculated using the point cloud bounding box. The patch with the highest similarity is selected as the homonymous patch, and its contour is extracted. Finally, the constrained 4PCS method is used for coarse registration of the point cloud, followed by refinement using the ICP algorithm to improve registration accuracy. The experimental results demonstrate that the proposed method achieves high application effectiveness without relying on the initial pose of the original point cloud, with an RMSE of less than 0.182 m. Compared to the traditional GICP and NDT algorithms, the improved 4PCS registration method proposed in this paper show a 30.8% improvement in accuracy and a 58.1% improvement in efficiency. Additionally, it exhibits high registration accuracy and robustness when the source point cloud and the target point cloud are too large.Aiming at the airborne LiDAR point cloud data of building roofs lacking prior pose information, this paper proposes a registration method that combines roof surface segmentation and the improved four-point consistent set(4PCS) algorithm. Firstly, the roof surface of the source and target point cloud is extracted based on a roof seed point. Next, the similarity between patches of the source point cloud and the roof surface point cloud in the target point cloud is calculated using the point cloud bounding box. The patch with the highest similarity is selected as the homonymous patch, and its contour is extracted. Finally, the constrained 4PCS method is used for coarse registration of the point cloud, followed by refinement using the ICP algorithm to improve registration accuracy. The experimental results demonstrate that the proposed method achieves high application effectiveness without relying on the initial pose of the original point cloud, with an RMSE of less than 0.182 m. Compared to the traditional GICP and NDT algorithms, the improved 4PCS registration method proposed in this paper show a 30.8% improvement in accuracy and a 58.1% improvement in efficiency. Additionally, it exhibits high registration accuracy and robustness when the source point cloud and the target point cloud are too large.
- Dec. 17, 2025
- APPLIED LASER
- Vol. 45, Issue 10, 179 (2025)
- DOI：10.14128/j.cnki.al.20254510.179
Dissolved Gas Detection in Transformer Oil Based on Tunable Diode Laser Absorption Spectrum
Song Ke, Li Zhenghong, Luo Yuan, and Chen Miao
Oil-immersed power transformer, especially the ultra-high voltage power transformer as the hub equipment in the power transmission and transformation system, its safe operation directly affects the safety and stability of the power system. Oil dissolved gas analysis is currently recognized at home and abroad to determine the oil-immersed power transformer early latent failure of one of the most effective methods.The available transformer online monitoring method performs the high maintenance cost and poor stability. In order to realize high-precision detection of gases, include hydrogen, methane, acetylene, ethylene, ethane, carbon monoxide, carbon dioxide, with low maintenance cost, this paper proposes an online monitoring method for dissolved gases in transformer insulation oil based on Tunable Diode Laser Absorption Spectrum. In order to verify the effectiveness of this method, a laser spectroscopy detection system for dissolved gases in transformer oil is designed. The results show that the relative standard deviation of the system designed in this paper is less than 5% in the measurement of different oil samples, and the measurement error meets Q/GDW 10536-2021.Moreover, the system has been applied to industrial sites, characterized with accurate, reliable detection results, maintenance-free operation.Oil-immersed power transformer, especially the ultra-high voltage power transformer as the hub equipment in the power transmission and transformation system, its safe operation directly affects the safety and stability of the power system. Oil dissolved gas analysis is currently recognized at home and abroad to determine the oil-immersed power transformer early latent failure of one of the most effective methods.The available transformer online monitoring method performs the high maintenance cost and poor stability. In order to realize high-precision detection of gases, include hydrogen, methane, acetylene, ethylene, ethane, carbon monoxide, carbon dioxide, with low maintenance cost, this paper proposes an online monitoring method for dissolved gases in transformer insulation oil based on Tunable Diode Laser Absorption Spectrum. In order to verify the effectiveness of this method, a laser spectroscopy detection system for dissolved gases in transformer oil is designed. The results show that the relative standard deviation of the system designed in this paper is less than 5% in the measurement of different oil samples, and the measurement error meets Q/GDW 10536-2021.Moreover, the system has been applied to industrial sites, characterized with accurate, reliable detection results, maintenance-free operation.
- Dec. 17, 2025
- APPLIED LASER
- Vol. 45, Issue 10, 169 (2025)
- DOI：10.14128/j.cnki.al.20254510.169
Flatness Error Measurement of Elevator Guide Rail Based on Laser Scanning Technology
Chen Ze′ao, Wang Junyuan, Du Wenhua, Fan Yingcheng, and Wei Kai
Aiming at the requirement of flatness error measurement of elevator T-guide rail, a 3D laser scanning measuring system is built to collect data of target plane and calibrate the measuring system.At the same time, a hybrid optimization algorithm for simulating plant growth and genetics was proposed.Firstly, the mathematical model of flatness error evaluation with minimum region method is established. Secondly, on the basis of simulating plant growth algorithm, genetic algorithm is introduced to initialize the growth point. In the search phase, the multi-growth point strategy is adopted, and genetic algorithm is introduced again to improve the global search ability, so as to avoid falling into the local optimal solution.Finally, after verifying the effectiveness of the algorithm, the algorithm is applied to the flatness error measurement of elevator T-guide rail. The experimental results show that the algorithm is better than LSM, GA, PGSA and PSO in calculation accuracy and time.The final measuring result of elevator guide rail is similar to that of CMM, which proves the accuracy of the algorithm and measuring system.Content of abstractAiming at the requirement of flatness error measurement of elevator T-guide rail, a 3D laser scanning measuring system is built to collect data of target plane and calibrate the measuring system.At the same time, a hybrid optimization algorithm for simulating plant growth and genetics was proposed.Firstly, the mathematical model of flatness error evaluation with minimum region method is established. Secondly, on the basis of simulating plant growth algorithm, genetic algorithm is introduced to initialize the growth point. In the search phase, the multi-growth point strategy is adopted, and genetic algorithm is introduced again to improve the global search ability, so as to avoid falling into the local optimal solution.Finally, after verifying the effectiveness of the algorithm, the algorithm is applied to the flatness error measurement of elevator T-guide rail. The experimental results show that the algorithm is better than LSM, GA, PGSA and PSO in calculation accuracy and time.The final measuring result of elevator guide rail is similar to that of CMM, which proves the accuracy of the algorithm and measuring system.Content of abstract
- Dec. 17, 2025
- APPLIED LASER
- Vol. 45, Issue 10, 161 (2025)
- DOI：10.14128/j.cnki.al.20254510.161
Research on Circuit Defect Detection System Based on Multi-Wavelength and Multi-Gradient
Feng Yuxiang, Ju Xiang, Li Yongwei, and Sun Haifeng
To enhance the accuracy of circuit board defect detection and minimize missed or false identifications, a defect detection system based on multi-wavelength combined irradiation was developed. A multi-wavelength and multi-gradient layered weighted recognition algorithm was designed to achieve different imaging effects for different types of defects using different wavelengths. The system uses multiple light sources with different center wavelengths to illuminate the same test area, and uses multiple illumination intensities to form a gradient illumination at the same wavelength, thus forming a set of test images. Comparative analysis of multi-wavelength and intensity-gradient irradiation results enables maximum contrast optimization for distinct defect categories. Experimental validation utilized three characteristic wavelengths combined with four grayscale gradients. The results showed that 295 nm had the best recognition effect on mouse bite defects and 555 nm had the best recognition effect on short circuit and bridging defects. The recognition effect of gray gradient 1 on burrs and gray gradient 3 on defects with missing holes is the best. The average defect recognition accuracy of this algorithm is 93.8%, and its comprehensive performance is better than YOLOv5 algorithm and broadband light source detection method, which has better practicality.To enhance the accuracy of circuit board defect detection and minimize missed or false identifications, a defect detection system based on multi-wavelength combined irradiation was developed. A multi-wavelength and multi-gradient layered weighted recognition algorithm was designed to achieve different imaging effects for different types of defects using different wavelengths. The system uses multiple light sources with different center wavelengths to illuminate the same test area, and uses multiple illumination intensities to form a gradient illumination at the same wavelength, thus forming a set of test images. Comparative analysis of multi-wavelength and intensity-gradient irradiation results enables maximum contrast optimization for distinct defect categories. Experimental validation utilized three characteristic wavelengths combined with four grayscale gradients. The results showed that 295 nm had the best recognition effect on mouse bite defects and 555 nm had the best recognition effect on short circuit and bridging defects. The recognition effect of gray gradient 1 on burrs and gray gradient 3 on defects with missing holes is the best. The average defect recognition accuracy of this algorithm is 93.8%, and its comprehensive performance is better than YOLOv5 algorithm and broadband light source detection method, which has better practicality.
- Dec. 17, 2025
- APPLIED LASER
- Vol. 45, Issue 10, 154 (2025)
- DOI：10.14128/j.cnki.al.20254510.154
Investigating on Characteristics of High Power Pulsed Laser Cleaning Mold
Jin Lunping, Wu Yuanming, Wang Weicheng, Li Feiyang, Gao Zhanxiang, and Zhu Haihong
In order to provide a green method for cleaning automotive tire mold, offline laser cleaning of automotive tire mold was carried out by using self-developed 1 000 W high-power pulsed laser cleaning equipment and process parameters in this paper. The characteristics of the laser cleaned mold were tested and analyzed. The results show that the high power pulsed laser cleaning can effectively remove pollutants from the mold surface by using the optimal process parameters while aluminum alloy tire mold or carbon steel tire mold. The surface roughness, microhardness, and wear resistance of the mold are slightly improved because of the tiny laser ablation. After laser cleaning, the pattern of the mold surface has no obvious deformation, the flatness of the parting surface is maintained below 0.02 mm, and the mechanical properties whether at room temperature nor high temperature have little change. It is proved that the developed high power pulsed laser cleaning equipment and process can remove surface pollutants from the mold without damaging and with high efficiency, new equipment can be provided for efficient and green cleaning of tire molds.In order to provide a green method for cleaning automotive tire mold, offline laser cleaning of automotive tire mold was carried out by using self-developed 1 000 W high-power pulsed laser cleaning equipment and process parameters in this paper. The characteristics of the laser cleaned mold were tested and analyzed. The results show that the high power pulsed laser cleaning can effectively remove pollutants from the mold surface by using the optimal process parameters while aluminum alloy tire mold or carbon steel tire mold. The surface roughness, microhardness, and wear resistance of the mold are slightly improved because of the tiny laser ablation. After laser cleaning, the pattern of the mold surface has no obvious deformation, the flatness of the parting surface is maintained below 0.02 mm, and the mechanical properties whether at room temperature nor high temperature have little change. It is proved that the developed high power pulsed laser cleaning equipment and process can remove surface pollutants from the mold without damaging and with high efficiency, new equipment can be provided for efficient and green cleaning of tire molds.
- Dec. 17, 2025
- APPLIED LASER
- Vol. 45, Issue 10, 142 (2025)
- DOI：10.14128/j.cnki.al.20254510.142
Research on Laser Cleaning of YSZ Thermal Barrier Coating on the Surface of Aircraft Turbine Engine Blades
Zhong Hongping, Sun Shuo, Li Duosheng, Chen Jiawei, Ye Yin, Qiu Yanqin, and Wu Meng
The surface thermal barrier coating of the turbine blades was damaged or even fall off during the long-term service, making the engine unusable. It is necessary to remove it and then repaint it for use. Conventional cleaning methods are difficult to effectively remove it. In this paper, we develops a novel cleaning method that uses nanosecond pulse laser to clean the surface of turbine engine blades, and the microstructure and mechanical properties wereinvestigated respectively. The results show that when the laser power is 20 W, the nickel-based alloy of the turbine blade can be well retained, and when the laser power is higher than 20 W, the surface was ablated after cleaning, and the surface damage of the matrix was aggravated with the increase of power. Finally, the best parameters for laser cleaning of thermal barrier coating are as follows: laser power 20 W, frequency 400 kHz, pulse width 400 ns, sweeping speed 600 mm/s, line spacing 0.030 mm, after repeated cleaning for five times, the thermal barrier coating on the surface of the blade can be completely removed. The hardness of the sample after laser cleaning is 101.42% of the original sample, which better retains the original mechanical properties.The surface thermal barrier coating of the turbine blades was damaged or even fall off during the long-term service, making the engine unusable. It is necessary to remove it and then repaint it for use. Conventional cleaning methods are difficult to effectively remove it. In this paper, we develops a novel cleaning method that uses nanosecond pulse laser to clean the surface of turbine engine blades, and the microstructure and mechanical properties wereinvestigated respectively. The results show that when the laser power is 20 W, the nickel-based alloy of the turbine blade can be well retained, and when the laser power is higher than 20 W, the surface was ablated after cleaning, and the surface damage of the matrix was aggravated with the increase of power. Finally, the best parameters for laser cleaning of thermal barrier coating are as follows: laser power 20 W, frequency 400 kHz, pulse width 400 ns, sweeping speed 600 mm/s, line spacing 0.030 mm, after repeated cleaning for five times, the thermal barrier coating on the surface of the blade can be completely removed. The hardness of the sample after laser cleaning is 101.42% of the original sample, which better retains the original mechanical properties.
- Dec. 17, 2025
- APPLIED LASER
- Vol. 45, Issue 10, 132 (2025)
- DOI：10.14128/j.cnki.al.20254510.132
Study on Laser Copying Cleaning of Large Area Aircraft Skin Coating
Qiu Yanqin, Sun Shuo, Li Duosheng, Ye Yin, Zhong Hongping, and Wu Meng
Due to the large and irregular area of the aircraft skin, it is difficult to remove the surface coating. In this paper, a nanosecond pulsed laser was used to clean the surface coating of the irregular large area of aluminum alloy aircraft skin. Three-dimension scanner was used to collect aircraft skin point cloud data and then process the model. Command programming was used to carry out the cleaning path of the aircraft skin copying laser cleaning. The influence of different path planning on the aircraft skin copying laser cleaning effect was studied. The samples were analyzed by scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), mechanical properties testing and low cycle fatigue test. The results show that, after the optimized path for copying laser cleaning, the coating was cleaned uniformly and completely. The tensile strength of the cleaned skin increased from 403.04 MPa to 418.37 MPa, and the fatigue life increased from 34 160 cycles to 52 291 cycles. The mechanical properties of the skin slightly increased and developed a non-destructive cleaning of irregular aircraft skin. The research results provide a reference for the feasibility of laser cleaning of large irregular components.Due to the large and irregular area of the aircraft skin, it is difficult to remove the surface coating. In this paper, a nanosecond pulsed laser was used to clean the surface coating of the irregular large area of aluminum alloy aircraft skin. Three-dimension scanner was used to collect aircraft skin point cloud data and then process the model. Command programming was used to carry out the cleaning path of the aircraft skin copying laser cleaning. The influence of different path planning on the aircraft skin copying laser cleaning effect was studied. The samples were analyzed by scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), mechanical properties testing and low cycle fatigue test. The results show that, after the optimized path for copying laser cleaning, the coating was cleaned uniformly and completely. The tensile strength of the cleaned skin increased from 403.04 MPa to 418.37 MPa, and the fatigue life increased from 34 160 cycles to 52 291 cycles. The mechanical properties of the skin slightly increased and developed a non-destructive cleaning of irregular aircraft skin. The research results provide a reference for the feasibility of laser cleaning of large irregular components.
- Dec. 17, 2025
- APPLIED LASER
- Vol. 45, Issue 10, 115 (2025)
- DOI：10.14128/j.cnki.al.20254510.115
OpticsNatural ScienceEngineeringAgricultureMedical ScienceInterdisciplinaryMultidisciplinaryAll Subjects
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Optics Frontier—The 17th International Conference on Information Optics and Photonics (CIOP 2026)
Dec. 15, 2025
Journal Slide
Dec. 11, 2025
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Dec. 11, 2025
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Dec. 11, 2025
Theme Issue on Time-Varying Photonics (2025)
Submission Open:10 December 2025; Submission Deadline: 30 April 2026
Theme Issue on Time-Varying Photonics (2025)
Submission Open:10 December 2025; Submission Deadline: 30 April 2026
Special Issue on Advanced Direct Drive Laser Driven Fusion Research and Technology (2025)
Submission Open:1 August 2025; Submission Deadline: 30 November 2025
Editor (s): Dimitri Batani, Sebastien Le Pape, Jianqiang Zhu, Ping Zhu
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