Map
WeChat
Email alert
RSS2023 Vol. 47, No. 1
Display Method:
[Abstract]
[PDF 246KB]
2023, 47(1): 1-12.
doi: 10.7510/jgjs.issn.1001-3806.2023.01.001
[FullText HTML]
Abstract:
Extreme ultraviolet (EUV) lithography is the most important part of the "neck" technology for chips. EUV lithography technology has been widely used in the manufacturing of integrated circuit chips with the most advanced process nodes. Its research and development cross integrates the knowledge of optics, machinery, electronics, control, software, materials, mathematics, physics and other disciplines. The development of EUV lithography reflects the evolution of joint research and development worldwide, and openness and cooperation are the main themes in the development process. The development history of EUV lithography and the major projects and institutions involved were reviewed. The flexible international cooperation route of ASML, the world's only EUV lithography manufacturer, was discussed. The research and development trends of representative research and development institutions in the world since 1997 and the relationship with the development of EUV lithography were analyzed. The influence of worldwide cooperation among participating institutions on the development of EUV lithography was described in detail. This research provides some enlightenment and reference for the research and development of advanced lithography machines and other similar high-end equipment.
Extreme ultraviolet (EUV) lithography is the most important part of the "neck" technology for chips. EUV lithography technology has been widely used in the manufacturing of integrated circuit chips with the most advanced process nodes. Its research and development cross integrates the knowledge of optics, machinery, electronics, control, software, materials, mathematics, physics and other disciplines. The development of EUV lithography reflects the evolution of joint research and development worldwide, and openness and cooperation are the main themes in the development process. The development history of EUV lithography and the major projects and institutions involved were reviewed. The flexible international cooperation route of ASML, the world's only EUV lithography manufacturer, was discussed. The research and development trends of representative research and development institutions in the world since 1997 and the relationship with the development of EUV lithography were analyzed. The influence of worldwide cooperation among participating institutions on the development of EUV lithography was described in detail. This research provides some enlightenment and reference for the research and development of advanced lithography machines and other similar high-end equipment.
2023, 47(1): 13-18.
doi: 10.7510/jgjs.issn.1001-3806.2023.01.002
Abstract:
In order to study the failure behavior of 7075 aluminum alloy under the combined loading of laser and external load, the joint loading experiments of 7075 aluminum alloy under different preloads and different laser power densities were carried out by using a tensile servo test machine with the maximum tension of 50 kN and a 6 kW continuous fiber laser system with the operating wavelength of 1070 nm. The tensile stress-time curve, temperature-time curve, fracture time-power density curve, and fracture temperature-power density curve were obtained. The effects of power density and preload on fracture process, fracture temperature, and fracture morphology were respectively analyzed. The results show that, under the same preload, the increase of laser power density leads to the nonlinear decline of fracture time, and the fracture temperature varies greatly depending on the size of preload. When the preload is large (330 MPa and 440 MPa), the fracture temperature increases slightly with the increase of power density, and when the preload is small (110 MPa and 220 MPa), the fracture temperature increases slightly with the increase of power density. Fracture temperature change rule is not monotonous, under the same laser power density, the fracture time decreases with the increase of preload, and the fracture behavior becomes similar with the increase of power density and the decrease of preload. At a certain power density (315 W/cm2 and 351 W/cm2), the fracture temperature increases first and then decreases with the increase of preload. The results further reveal the fracture mechanism of 7075 aluminum alloy.
In order to study the failure behavior of 7075 aluminum alloy under the combined loading of laser and external load, the joint loading experiments of 7075 aluminum alloy under different preloads and different laser power densities were carried out by using a tensile servo test machine with the maximum tension of 50 kN and a 6 kW continuous fiber laser system with the operating wavelength of 1070 nm. The tensile stress-time curve, temperature-time curve, fracture time-power density curve, and fracture temperature-power density curve were obtained. The effects of power density and preload on fracture process, fracture temperature, and fracture morphology were respectively analyzed. The results show that, under the same preload, the increase of laser power density leads to the nonlinear decline of fracture time, and the fracture temperature varies greatly depending on the size of preload. When the preload is large (330 MPa and 440 MPa), the fracture temperature increases slightly with the increase of power density, and when the preload is small (110 MPa and 220 MPa), the fracture temperature increases slightly with the increase of power density. Fracture temperature change rule is not monotonous, under the same laser power density, the fracture time decreases with the increase of preload, and the fracture behavior becomes similar with the increase of power density and the decrease of preload. At a certain power density (315 W/cm2 and 351 W/cm2), the fracture temperature increases first and then decreases with the increase of preload. The results further reveal the fracture mechanism of 7075 aluminum alloy.
2023, 47(1): 19-24.
doi: 10.7510/jgjs.issn.1001-3806.2023.01.003
Abstract:
In order to obtain strong multiple Fano resonances, a metasurface composed of asymmetric nanosheet heterodimer was designed in the paper. Based on the finite element analysis method, the physical mechanism of Fano resonances was analyzed by the hybridization theory, and the different Fano responses resulted from different Fermi levels, structures parameters were analyzed. Results show that when the Fermi level of the graphene nanosheet increases, the Fano resonance peaks blue shift, and the intensity of graphene responses is enhanced, which causes that the local effect and absorption are enhanced accordingly. At the same time, with the increase of the asymmetry of the size and position of the nanosheet heterodimer, the asymmetry of Fano resonances also increases. The Fano resonances based on the simply graphene nanosheet heterodimer array are expected to be widely used in biosensor and related fields. The study provides theoretical reference for further experimental research.
In order to obtain strong multiple Fano resonances, a metasurface composed of asymmetric nanosheet heterodimer was designed in the paper. Based on the finite element analysis method, the physical mechanism of Fano resonances was analyzed by the hybridization theory, and the different Fano responses resulted from different Fermi levels, structures parameters were analyzed. Results show that when the Fermi level of the graphene nanosheet increases, the Fano resonance peaks blue shift, and the intensity of graphene responses is enhanced, which causes that the local effect and absorption are enhanced accordingly. At the same time, with the increase of the asymmetry of the size and position of the nanosheet heterodimer, the asymmetry of Fano resonances also increases. The Fano resonances based on the simply graphene nanosheet heterodimer array are expected to be widely used in biosensor and related fields. The study provides theoretical reference for further experimental research.
2023, 47(1): 25-31.
doi: 10.7510/jgjs.issn.1001-3806.2023.01.004
Abstract:
In order to compare laser lift-off thermal conductive effects by nanosecond laser and picosecond laser in GaN on AlN of micro light-emitting diode(micro-LED), an improved theoretical model of laser lift-off process for real-time ultraviolet light absorption and heat conduction was established. This model was used to calculate and analysis the thermal field distribution of GaN materials irradiated by various ultraviolet, laser pulses with different laser wavelength, laser pulse width, laser energy density. And the threshold conditions suitable for micro-LED devices of laser lift-off process by nanosecond laser and picosecond laser were obtained. The results show that laser pulse width, laser wavelength, and laser energy density are the key factors of laser lift-off process. The suitable laser wavelength includes 209 nm~365 nm ultraviolet band, and the laser lift-off effect of picosecond laser is better than that of nanosecond laser. Moreover, the shorter the pulse width and the shorter the wavelength of laser, the lower the threshold energy of laser pulse is needed for lift-off, and the smaller the thermal impact on the LED chip area. This research provides an important reference for the development of new laser lift-off equipment and related process applications.
In order to compare laser lift-off thermal conductive effects by nanosecond laser and picosecond laser in GaN on AlN of micro light-emitting diode(micro-LED), an improved theoretical model of laser lift-off process for real-time ultraviolet light absorption and heat conduction was established. This model was used to calculate and analysis the thermal field distribution of GaN materials irradiated by various ultraviolet, laser pulses with different laser wavelength, laser pulse width, laser energy density. And the threshold conditions suitable for micro-LED devices of laser lift-off process by nanosecond laser and picosecond laser were obtained. The results show that laser pulse width, laser wavelength, and laser energy density are the key factors of laser lift-off process. The suitable laser wavelength includes 209 nm~365 nm ultraviolet band, and the laser lift-off effect of picosecond laser is better than that of nanosecond laser. Moreover, the shorter the pulse width and the shorter the wavelength of laser, the lower the threshold energy of laser pulse is needed for lift-off, and the smaller the thermal impact on the LED chip area. This research provides an important reference for the development of new laser lift-off equipment and related process applications.
2023, 47(1): 32-40.
doi: 10.7510/jgjs.issn.1001-3806.2023.01.005
Abstract:
In order to study the obstacle avoidance control effect of unmanned aerial vehicle (UAV) anti-collision formation in the environment of strong electromagnetic interference, the ultraviolet light communication model between UAV formations was adopted, and the traditional artificial potential field method was improved. The potential field function of the UAV and the obstacle was established, with which the local obstacle avoidance while the UAV formation was flying was realized. The results show that with the improved artificial potential field method, the obstacle avoidance time reduces by 7.38% and the total obstacle avoidance path reduces by 5.8% compared with the traditional artificial potential field method under the same conditions. The improved obstacle avoidance algorithm is applied to the formation. It can realize the obstacle avoidance between the drones and the avoidance of external obstacles, the formation can maintain a fixed formation to fly to the target point. This result has certain application value for the research of UAV formation obstacle avoidance in strong electromagnetic interference environment.
In order to study the obstacle avoidance control effect of unmanned aerial vehicle (UAV) anti-collision formation in the environment of strong electromagnetic interference, the ultraviolet light communication model between UAV formations was adopted, and the traditional artificial potential field method was improved. The potential field function of the UAV and the obstacle was established, with which the local obstacle avoidance while the UAV formation was flying was realized. The results show that with the improved artificial potential field method, the obstacle avoidance time reduces by 7.38% and the total obstacle avoidance path reduces by 5.8% compared with the traditional artificial potential field method under the same conditions. The improved obstacle avoidance algorithm is applied to the formation. It can realize the obstacle avoidance between the drones and the avoidance of external obstacles, the formation can maintain a fixed formation to fly to the target point. This result has certain application value for the research of UAV formation obstacle avoidance in strong electromagnetic interference environment.
2023, 47(1): 41-45.
doi: 10.7510/jgjs.issn.1001-3806.2023.01.006
Abstract:
In order to measure the change of liquid level near the warning value, a new optical fiber fusion splicer was used to fabricate a fiber optic sensor for measuring liquid level based on long-period fiber grating with tapered structure. The refractive index sensitivity of the liquid level sensing experimental system was built to measure the length of the optical fiber immersed in the liquid. The results show that in the liquid level measurement range of 0 mm~12 mm, the peak wavelength sensitivity and transmission power sensitivity of the optical fiber liquid level sensor were 0.700 nm/mm and 1.377 dB/nm, respectively. The sensor is more accurate in measuring the liquid level change, and the grating method mentioned above can effectively solve the problems of asymmetric mode coupling and high polarization dependence in the traditional long-period fiber grating, and it has the advantages of simplicity, low cost and wide application prospects.
In order to measure the change of liquid level near the warning value, a new optical fiber fusion splicer was used to fabricate a fiber optic sensor for measuring liquid level based on long-period fiber grating with tapered structure. The refractive index sensitivity of the liquid level sensing experimental system was built to measure the length of the optical fiber immersed in the liquid. The results show that in the liquid level measurement range of 0 mm~12 mm, the peak wavelength sensitivity and transmission power sensitivity of the optical fiber liquid level sensor were 0.700 nm/mm and 1.377 dB/nm, respectively. The sensor is more accurate in measuring the liquid level change, and the grating method mentioned above can effectively solve the problems of asymmetric mode coupling and high polarization dependence in the traditional long-period fiber grating, and it has the advantages of simplicity, low cost and wide application prospects.
2023, 47(1): 46-51.
doi: 10.7510/jgjs.issn.1001-3806.2023.01.007
Abstract:
The existing rail transit location and speed measurement method is easy to be interfered by the external environment and has instability. In order to solve these problems, based on the fiber grating with the characteristics of insulation, strong anti-interference, and corrosion resistance, a high precision train speed measurement and location system based on weak grating array combined with wave division and optical time-domain reflectometer (OTDR) technology was proposed. The absolute location requirement of grating points was realized by intensive multiplexing, and a data processing method was designed to calculate real-time speed and position according to the location results of different grating partitions and their wavelength drift rules. In order to verify the performance of the system, a simulated operating environment was built. And theoretical analysis and experimental verification were carried out. Experimental results show that centimeter-level positioning accuracy and 1 km/h speed measurement accuracy can be achieved with the proposed scheme, which has a wide application prospect in rail transit.
The existing rail transit location and speed measurement method is easy to be interfered by the external environment and has instability. In order to solve these problems, based on the fiber grating with the characteristics of insulation, strong anti-interference, and corrosion resistance, a high precision train speed measurement and location system based on weak grating array combined with wave division and optical time-domain reflectometer (OTDR) technology was proposed. The absolute location requirement of grating points was realized by intensive multiplexing, and a data processing method was designed to calculate real-time speed and position according to the location results of different grating partitions and their wavelength drift rules. In order to verify the performance of the system, a simulated operating environment was built. And theoretical analysis and experimental verification were carried out. Experimental results show that centimeter-level positioning accuracy and 1 km/h speed measurement accuracy can be achieved with the proposed scheme, which has a wide application prospect in rail transit.
2023, 47(1): 52-58.
doi: 10.7510/jgjs.issn.1001-3806.2023.01.008
Abstract:
In order to study the influence mechanism of WC microstructure evolution on crack generation in composite coating, three Ni50A/WC composite coatings were prepared by single-layer laser cladding, transition layer gradient cladding and double-layer cladding. The morphology and structure of coating, crack generation characteristics, and the causes of crack were analyzed. The influence of WC microstructure evolution on crack generation was then explored. The results show that the influence of microstructure evolution of WC by different cladding methods on crack generation is mainly caused by internal cracking of residual WC particles. Compared with the monolayer cladding coating, the content of residual WC particles decreased by 32.7% and 37.9% due to the absorption of more energy by the powder of double-layer cladding and gradient cladding coating, and the source of cracks in the coating was reduced. In addition, the mass fraction of W element in eutectic compounds decrease from 0.534 of monolayer cladding coating to 0.417 of double cladding coating and 0.386 of gradient cladding coating, which reduced the concentration of hard phase elements, composition segregation and cracking sensitivity of coating. This research has certain guiding significance to improve the cracking of laser cladding composite coating and improve the yield of composite coating.
In order to study the influence mechanism of WC microstructure evolution on crack generation in composite coating, three Ni50A/WC composite coatings were prepared by single-layer laser cladding, transition layer gradient cladding and double-layer cladding. The morphology and structure of coating, crack generation characteristics, and the causes of crack were analyzed. The influence of WC microstructure evolution on crack generation was then explored. The results show that the influence of microstructure evolution of WC by different cladding methods on crack generation is mainly caused by internal cracking of residual WC particles. Compared with the monolayer cladding coating, the content of residual WC particles decreased by 32.7% and 37.9% due to the absorption of more energy by the powder of double-layer cladding and gradient cladding coating, and the source of cracks in the coating was reduced. In addition, the mass fraction of W element in eutectic compounds decrease from 0.534 of monolayer cladding coating to 0.417 of double cladding coating and 0.386 of gradient cladding coating, which reduced the concentration of hard phase elements, composition segregation and cracking sensitivity of coating. This research has certain guiding significance to improve the cracking of laser cladding composite coating and improve the yield of composite coating.
2023, 47(1): 59-66.
doi: 10.7510/jgjs.issn.1001-3806.2023.01.009
Abstract:
In order to solve the problems of unknown angular resolution and point density variation of terrestrial laser point cloud, a classification method considering density change and unknown angular resolution was proposed in this paper. To improve the traditional point density calculation method, the angular resolution estimation method of random neighborhood analysis was presented. Then we combine angular resolution to propose a grid feature extraction method which takes density variation into account. The proposed method was tested on three datasets. The result shows that the error of our method is smaller than 0.002°, which can accurately estimate the angular resolution. And compared with traditional density feature, our method can improve the overall accuracy of point cloud classification, and perform well in the extraction of cars and pole. The angle resolution can be accurately estimated with this method, and the point cloud can be classified with higher accuracy, which can provide a reference for density adaptive processing of large-scale terrestrial laser point clouds.
In order to solve the problems of unknown angular resolution and point density variation of terrestrial laser point cloud, a classification method considering density change and unknown angular resolution was proposed in this paper. To improve the traditional point density calculation method, the angular resolution estimation method of random neighborhood analysis was presented. Then we combine angular resolution to propose a grid feature extraction method which takes density variation into account. The proposed method was tested on three datasets. The result shows that the error of our method is smaller than 0.002°, which can accurately estimate the angular resolution. And compared with traditional density feature, our method can improve the overall accuracy of point cloud classification, and perform well in the extraction of cars and pole. The angle resolution can be accurately estimated with this method, and the point cloud can be classified with higher accuracy, which can provide a reference for density adaptive processing of large-scale terrestrial laser point clouds.
2023, 47(1): 67-72.
doi: 10.7510/jgjs.issn.1001-3806.2023.01.010
Abstract:
For studying the micro features of cloud particles, a laser cloud particle imaging probe was developed by using laser imaging technology, homogenizing technology of Gaussian beam, and a high resolution array detector and a frame-extracting algorithm of image. The performance of the instrument was tested through simulation measure and actual flight experiment. The results show that for cloud particles of 25 μm~1550 μm with 25 μm resolution can be imaged with the developed instrument, and the error of particle-size measured is less than 9.5%. The particle shape of ice crystal watched conforms to the natural distribution of cloud particles, the particle-size distribution conforms to the exponential function with a determination coefficient between 0.58 and 0.97.The developed instrument can provide basic observation data for the study of cloud and precipitation microphysics.
For studying the micro features of cloud particles, a laser cloud particle imaging probe was developed by using laser imaging technology, homogenizing technology of Gaussian beam, and a high resolution array detector and a frame-extracting algorithm of image. The performance of the instrument was tested through simulation measure and actual flight experiment. The results show that for cloud particles of 25 μm~1550 μm with 25 μm resolution can be imaged with the developed instrument, and the error of particle-size measured is less than 9.5%. The particle shape of ice crystal watched conforms to the natural distribution of cloud particles, the particle-size distribution conforms to the exponential function with a determination coefficient between 0.58 and 0.97.The developed instrument can provide basic observation data for the study of cloud and precipitation microphysics.
2023, 47(1): 73-79.
doi: 10.7510/jgjs.issn.1001-3806.2023.01.011
Abstract:
In order to realize high-precision digital holographic phase unwrapping, a lightweight deep learning network based on MobilenetV3 integrated in the Unet network framework adopted, and the UMnet network designed to realize accurate unwrapping of holographic phase. The network lightweight attention mechanism and multi-scale convolution to enhance the network accuracy and generalization ability. At the same time, the hard-Swish activation function improve the network learning ability. The simulated data set used for network training, and the noise reduction ability of the generated network model tested, which verified by the test of the hologram of the actual sample. The results show that the structural similarity index of UMnet is 6.6% higher than that of deep learning phase unwrapping network. UMnet can realize digital holographic phase unwrapping simply, quickly and efficiently.
In order to realize high-precision digital holographic phase unwrapping, a lightweight deep learning network based on MobilenetV3 integrated in the Unet network framework adopted, and the UMnet network designed to realize accurate unwrapping of holographic phase. The network lightweight attention mechanism and multi-scale convolution to enhance the network accuracy and generalization ability. At the same time, the hard-Swish activation function improve the network learning ability. The simulated data set used for network training, and the noise reduction ability of the generated network model tested, which verified by the test of the hologram of the actual sample. The results show that the structural similarity index of UMnet is 6.6% higher than that of deep learning phase unwrapping network. UMnet can realize digital holographic phase unwrapping simply, quickly and efficiently.
2023, 47(1): 80-86.
doi: 10.7510/jgjs.issn.1001-3806.2023.01.012
Abstract:
To solve the problems of high density but uneven distribution of point cloud data collected by ummanned aerial vehicle (UAV) airborne lidar and incomplete information on the surface texture of insulators, a power grid insulator identification method based on airborne laser point cloud was proposed. Firstly, the histogram of the intensity value of different parts of the tower was analyzed, and the intensity value filter was used to remove most of the tower body point cloud; the principal component analysis method was then used to calculate the local point cloud eigenvalues. The local entropy function and spatial distribution characteristics based on the eigenvalues delete redundant flat area point clouds was built. Grid patching was used to avoid point cloud holes; finally, to solve the problem of low accuracy and slow speed of the traditional sample consensus initial alignment (SAC-IA) algorithm, the SAC-IA algorithm was improved to complete the pose estimation of the insulator by increasing the distance constraint relationship of the sampling point pair and adaptive adjustment parameters. The experimental results show that the insulators in the tower can be identified accurately and efficiently by using this method. And the running time is greatly reduced, and the extraction accuracy rate reaches 95.16%, which has good application value in UAV autonomous inspection route planning.
To solve the problems of high density but uneven distribution of point cloud data collected by ummanned aerial vehicle (UAV) airborne lidar and incomplete information on the surface texture of insulators, a power grid insulator identification method based on airborne laser point cloud was proposed. Firstly, the histogram of the intensity value of different parts of the tower was analyzed, and the intensity value filter was used to remove most of the tower body point cloud; the principal component analysis method was then used to calculate the local point cloud eigenvalues. The local entropy function and spatial distribution characteristics based on the eigenvalues delete redundant flat area point clouds was built. Grid patching was used to avoid point cloud holes; finally, to solve the problem of low accuracy and slow speed of the traditional sample consensus initial alignment (SAC-IA) algorithm, the SAC-IA algorithm was improved to complete the pose estimation of the insulator by increasing the distance constraint relationship of the sampling point pair and adaptive adjustment parameters. The experimental results show that the insulators in the tower can be identified accurately and efficiently by using this method. And the running time is greatly reduced, and the extraction accuracy rate reaches 95.16%, which has good application value in UAV autonomous inspection route planning.
2023, 47(1): 87-91.
doi: 10.7510/jgjs.issn.1001-3806.2023.01.013
Abstract:
In order to reflect the distribution of the performance of each region on the geometric scale of the device, a laser beam with a wavelength of 852 nm and an adjustable focusing area was used to act on the surface of the P-N junction microregion of the CdTe thin-film solar cell to generate a localized induced photocurrent. By setting the step-by-step method of the sample stage, the micro-region spectral response distribution map of the measured device within the geometric area range was obtained, and a more intuitive device current distribution uniformity and P-N junction characteristics were obtained. The results show that the relationship between the deposition and post-processing parameters and material properties that are closely related to the CdS/CdTe heterojunction fabrication technology can be simplified and cost-effectively established by using this test method, and then the heterojunction interface distribution uniformity and solar cells can be obtained. The corresponding relationship of the uniformity of I-V characteristic parameters provides experimental test basis for improving the performance of solar cells.
In order to reflect the distribution of the performance of each region on the geometric scale of the device, a laser beam with a wavelength of 852 nm and an adjustable focusing area was used to act on the surface of the P-N junction microregion of the CdTe thin-film solar cell to generate a localized induced photocurrent. By setting the step-by-step method of the sample stage, the micro-region spectral response distribution map of the measured device within the geometric area range was obtained, and a more intuitive device current distribution uniformity and P-N junction characteristics were obtained. The results show that the relationship between the deposition and post-processing parameters and material properties that are closely related to the CdS/CdTe heterojunction fabrication technology can be simplified and cost-effectively established by using this test method, and then the heterojunction interface distribution uniformity and solar cells can be obtained. The corresponding relationship of the uniformity of I-V characteristic parameters provides experimental test basis for improving the performance of solar cells.
2023, 47(1): 92-97.
doi: 10.7510/jgjs.issn.1001-3806.2023.01.014
Abstract:
In order to improve the accuracy of long-distance speed measurement, a signal processing method based on wavelet decomposition reconstruction (WDR) combined with fast Fourier transform (FFT) was adopt in this paper. Theoretical analysis and experimental verification were carried out, and the pulse coherent velocimetry data of hard targets at different speeds were obtained. The results show that the targets with a velocity change of 0.02 m/s can be accurately resolved by using the WDR & FFT method. This research provides a reference for the high-resolution velocity measurement of long-distance and low-velocity targets.
In order to improve the accuracy of long-distance speed measurement, a signal processing method based on wavelet decomposition reconstruction (WDR) combined with fast Fourier transform (FFT) was adopt in this paper. Theoretical analysis and experimental verification were carried out, and the pulse coherent velocimetry data of hard targets at different speeds were obtained. The results show that the targets with a velocity change of 0.02 m/s can be accurately resolved by using the WDR & FFT method. This research provides a reference for the high-resolution velocity measurement of long-distance and low-velocity targets.
2023, 47(1): 98-102.
doi: 10.7510/jgjs.issn.1001-3806.2023.01.015
Abstract:
In order to solve the problem of poor plate-making quality caused by distortion and field curvature of the plate-making lens of the external drum thermal computer to plate (CTP)equipment, a low-distortion and low-field-curvature plate-making lens optical system was designed using ZEMAX software. Tolerance analysis and experimental verification have been carried out. The results show that the optical system is consisted of six lenses, the working wavelength is 830 nm, the field curvature is less than 1 μm, the distortion is less than 0.1%, and the modulation transfer function is greater than 0.7 at the full field of view of 200 lp/mm. All the lenses in this system are designed with a standard spherical surface, and the plate-making effect is good, which can meet the actual plate-making production needs, and has a certain market prospect.
In order to solve the problem of poor plate-making quality caused by distortion and field curvature of the plate-making lens of the external drum thermal computer to plate (CTP)equipment, a low-distortion and low-field-curvature plate-making lens optical system was designed using ZEMAX software. Tolerance analysis and experimental verification have been carried out. The results show that the optical system is consisted of six lenses, the working wavelength is 830 nm, the field curvature is less than 1 μm, the distortion is less than 0.1%, and the modulation transfer function is greater than 0.7 at the full field of view of 200 lp/mm. All the lenses in this system are designed with a standard spherical surface, and the plate-making effect is good, which can meet the actual plate-making production needs, and has a certain market prospect.
2023, 47(1): 103-107.
doi: 10.7510/jgjs.issn.1001-3806.2023.01.016
Abstract:
In order to study the influence of the initial phase of ultrashort and super elliptically polarized laser on the radiation characteristics of high-energy electrons, the collision model of high-energy electrons and high-energy laser field was constructed by Lorentz equation and electron energy equation, and the numerical simulation was carried out by MATLAB. The data and images of electron trajectory and power and energy distribution of spatial radiation of laser field were obtained. The 3-D radiation characteristics corresponding to different initial laser phases were studied. The results show that when the laser pulse strikes the electron, the electron produces radiation, and the radiation power presents a double peak shape. The radiation power image of high-energy electrons shows symmetrical double peaks when the initial phase is 0°, 180° and 360°. The conclusion provides a certain basis for the study of initial phase 3-D inverse detection of ultrashort and ultra strong elliptically polarized laser.
In order to study the influence of the initial phase of ultrashort and super elliptically polarized laser on the radiation characteristics of high-energy electrons, the collision model of high-energy electrons and high-energy laser field was constructed by Lorentz equation and electron energy equation, and the numerical simulation was carried out by MATLAB. The data and images of electron trajectory and power and energy distribution of spatial radiation of laser field were obtained. The 3-D radiation characteristics corresponding to different initial laser phases were studied. The results show that when the laser pulse strikes the electron, the electron produces radiation, and the radiation power presents a double peak shape. The radiation power image of high-energy electrons shows symmetrical double peaks when the initial phase is 0°, 180° and 360°. The conclusion provides a certain basis for the study of initial phase 3-D inverse detection of ultrashort and ultra strong elliptically polarized laser.
2023, 47(1): 108-114.
doi: 10.7510/jgjs.issn.1001-3806.2023.01.017
Abstract:
In order to meet the practical needs of high-power semiconductor laser pulse application, aiming at the problem of flat top current drop in a single pulse and the reduction of current stability in the case of repeatability, a high-precision and high stability pulse driving power supply with adjustable multi parameters and wide range was designed. The high-power field-effect transistor was took as the core of the power supply. The rising edge regulation and gate control voltage compensation in a single pulse can be obtianed through the high-precision timing waveform generated by the field-programmable gate array. The high and stable output of current under repeated frequency operation was realized through the closed-loop control scheme of microcontroller combined with current sampling. The results show that, when the output current, pulse width, and repetition rate of the loaded diode with maximum power output is respectively 100 A, 400 μs, and 1 kHz, the overshoot amplitude of the rising edge of the driving current is less than 0.5%, the current attenuation in a single pulse is less than 0.2%, and the instability of the repetition rate pulse is less than 0.1%. When the semiconductor laser is driven under the same output conditions, the optical power overshoot in a single pulse is less than 2%, and the instability of repeated optical pulses is less than 0.2%. This research is helpful to improve the stability of pulse current of pulse power supply, and has certain reference significance for the improvement of existing pulse power supply structure.
In order to meet the practical needs of high-power semiconductor laser pulse application, aiming at the problem of flat top current drop in a single pulse and the reduction of current stability in the case of repeatability, a high-precision and high stability pulse driving power supply with adjustable multi parameters and wide range was designed. The high-power field-effect transistor was took as the core of the power supply. The rising edge regulation and gate control voltage compensation in a single pulse can be obtianed through the high-precision timing waveform generated by the field-programmable gate array. The high and stable output of current under repeated frequency operation was realized through the closed-loop control scheme of microcontroller combined with current sampling. The results show that, when the output current, pulse width, and repetition rate of the loaded diode with maximum power output is respectively 100 A, 400 μs, and 1 kHz, the overshoot amplitude of the rising edge of the driving current is less than 0.5%, the current attenuation in a single pulse is less than 0.2%, and the instability of the repetition rate pulse is less than 0.1%. When the semiconductor laser is driven under the same output conditions, the optical power overshoot in a single pulse is less than 2%, and the instability of repeated optical pulses is less than 0.2%. This research is helpful to improve the stability of pulse current of pulse power supply, and has certain reference significance for the improvement of existing pulse power supply structure.
2023, 47(1): 115-120.
doi: 10.7510/jgjs.issn.1001-3806.2023.01.018
Abstract:
In order to achieve sub-diffraction limited imaging of the distant objects with telescope under the dynamical disturbance of the atmospheric turbulence, the optical super-oscillation phenomenon was utilized to locally compress the point spread function of the telescope. Theoretical study was performed to investigate the imaging resolution improvement with super-oscillation phenomenon. In the case of the modest atmospheric turbulence, the adaptive optics closed-loop root mean square of the simulated residual wave front error is about 1/15 of wavelength. The numerical full width at half maxima of the super-oscillation spot is about 0.75 times of the Airy spot at the working wavelength of 632.8 nm. In addition, the imaging results of the two holes with different center-to-center distances validate that the resolving ability of the super-oscillation telescope is about 0.80 times of the Rayleigh criterion. Different root mean square of the residual wave front error would result in the diffractive compression ratio of the telescope's point spread function and the improvement of the imaging resolution. It is believed that this study provides a practical method for the high-precision star positioning and the super-resolution telescope etc.
In order to achieve sub-diffraction limited imaging of the distant objects with telescope under the dynamical disturbance of the atmospheric turbulence, the optical super-oscillation phenomenon was utilized to locally compress the point spread function of the telescope. Theoretical study was performed to investigate the imaging resolution improvement with super-oscillation phenomenon. In the case of the modest atmospheric turbulence, the adaptive optics closed-loop root mean square of the simulated residual wave front error is about 1/15 of wavelength. The numerical full width at half maxima of the super-oscillation spot is about 0.75 times of the Airy spot at the working wavelength of 632.8 nm. In addition, the imaging results of the two holes with different center-to-center distances validate that the resolving ability of the super-oscillation telescope is about 0.80 times of the Rayleigh criterion. Different root mean square of the residual wave front error would result in the diffractive compression ratio of the telescope's point spread function and the improvement of the imaging resolution. It is believed that this study provides a practical method for the high-precision star positioning and the super-resolution telescope etc.
2023, 47(1): 121-126.
doi: 10.7510/jgjs.issn.1001-3806.2023.01.019
Abstract:
In order to estimate the noise levels of hyperspectral images under ground-based imaging conditions accurately, a residual-scaled local standard deviations (RLSD) method after edge elimination was proposed. Firstly, the obtained hyperspectral image was divided into several sub-blocks of appropriate size, and then the edge information of the image was detected by using Canny edge detection operator, and the sub-blocks containing edges were judged and eliminated. The noise estimation of the uniform sub-blocks after the removal of edge sub-blocks was carried out by the method of multiple linear regression and residual error. The total error of noise was 1.985×103 and 2.197×103 for different sub-regions of the same land-based hyperspectral images by 4×4 pixel and 8×8 pixel segmentation. The results show that the proposed noise estimation method is robust to the noise evaluation of hyperspectral images under the condition of land-based imaging, which provides a reference for the subsequent processing and application of land-based hyperspectral images.
In order to estimate the noise levels of hyperspectral images under ground-based imaging conditions accurately, a residual-scaled local standard deviations (RLSD) method after edge elimination was proposed. Firstly, the obtained hyperspectral image was divided into several sub-blocks of appropriate size, and then the edge information of the image was detected by using Canny edge detection operator, and the sub-blocks containing edges were judged and eliminated. The noise estimation of the uniform sub-blocks after the removal of edge sub-blocks was carried out by the method of multiple linear regression and residual error. The total error of noise was 1.985×103 and 2.197×103 for different sub-regions of the same land-based hyperspectral images by 4×4 pixel and 8×8 pixel segmentation. The results show that the proposed noise estimation method is robust to the noise evaluation of hyperspectral images under the condition of land-based imaging, which provides a reference for the subsequent processing and application of land-based hyperspectral images.
2023, 47(1): 127-134.
doi: 10.7510/jgjs.issn.1001-3806.2023.01.020
Abstract:
In order to improve the real-time performance of state sensing, the slope-assisted techniqueand the least-squares spectrum fit method based on the pseudo-Voigt model were introduced into the strain measurement of optical fiber composite overhead lines. The programs about the least squares spectrum fitting method and the slope-assisted technique based on the pseudo-Voigt model were written and applied to the strain measurement along an optical fiber composite overhead line. Based on the measured Brillouin spectra, the influence of the signal-to-noise ratio (SNR) of the working point gain and the Brillouin frequency shift (BFS) on the accuracy of the slope-assisted technique was systematically investigated. The results reveal that the BFS error decreases exponentially with SNR. The BFS error decreases rapidly and then increases slightly with the difference between BFS and working point frequency. The strain error of the slope-assisted technique is less than 60 με when the SNR of Brillouin gain at the working point is not less than 25 dB and at the same time, the frequency at the working point is always less or larger than the BFS. In addition, the corresponding critical SNR of 60 με is presented for different BFSs, and the critical SNR corresponding to different cases can be obtained by interpolation. The measurement time and computation time of the slope-assisted technique are about 1/161 and 1/600 of that of the spectrum fitting method, respectively. The work provides a reference for improving the real-time performance of sate sensing of intelligent optical fiber composite overhead lines.
In order to improve the real-time performance of state sensing, the slope-assisted techniqueand the least-squares spectrum fit method based on the pseudo-Voigt model were introduced into the strain measurement of optical fiber composite overhead lines. The programs about the least squares spectrum fitting method and the slope-assisted technique based on the pseudo-Voigt model were written and applied to the strain measurement along an optical fiber composite overhead line. Based on the measured Brillouin spectra, the influence of the signal-to-noise ratio (SNR) of the working point gain and the Brillouin frequency shift (BFS) on the accuracy of the slope-assisted technique was systematically investigated. The results reveal that the BFS error decreases exponentially with SNR. The BFS error decreases rapidly and then increases slightly with the difference between BFS and working point frequency. The strain error of the slope-assisted technique is less than 60 με when the SNR of Brillouin gain at the working point is not less than 25 dB and at the same time, the frequency at the working point is always less or larger than the BFS. In addition, the corresponding critical SNR of 60 με is presented for different BFSs, and the critical SNR corresponding to different cases can be obtained by interpolation. The measurement time and computation time of the slope-assisted technique are about 1/161 and 1/600 of that of the spectrum fitting method, respectively. The work provides a reference for improving the real-time performance of sate sensing of intelligent optical fiber composite overhead lines.
2023, 47(1): 135-139.
doi: 10.7510/jgjs.issn.1001-3806.2023.01.021
Abstract:
In order to explore the gradient changes of super laser polarization parameters based on the high energy electron motion and the influence of radiation characteristics, based on the basic equation of electromagnetism, a relativistic electron acceleration model was derived and set up with the initial momentum of 0. Then a numerical simulation program of no approximation was developed for iterative calculation and theoretical analysis. Visualized data of single electron motion and space radiation under different polarization parameters were obtained. The results show that with the increase of the polarization parameter δ from 0 to 1, the trajectory of the electron gradually changes from 2-D plane oscillation to 3-D spiral, and the amplitude of rotation increases gradually, and the trajectory projection tends to be positive circle. The spatial distribution of electron power radiation gradually changed from planar linear to 3-D vortex, and gradually changed from up-down needle-like bifurcation to smooth connection. The general change trend can be divided into four stages according to morphology: δ=0, δ∈(0, 0.6], δ∈(0.6, 0.99] and δ=1. The results provide a theoretical and numerical basis for the study of high-energy electron radiation from multiple perspectives, and are helpful for the accurate detection of super-strong laser parameters in practical applications.
In order to explore the gradient changes of super laser polarization parameters based on the high energy electron motion and the influence of radiation characteristics, based on the basic equation of electromagnetism, a relativistic electron acceleration model was derived and set up with the initial momentum of 0. Then a numerical simulation program of no approximation was developed for iterative calculation and theoretical analysis. Visualized data of single electron motion and space radiation under different polarization parameters were obtained. The results show that with the increase of the polarization parameter δ from 0 to 1, the trajectory of the electron gradually changes from 2-D plane oscillation to 3-D spiral, and the amplitude of rotation increases gradually, and the trajectory projection tends to be positive circle. The spatial distribution of electron power radiation gradually changed from planar linear to 3-D vortex, and gradually changed from up-down needle-like bifurcation to smooth connection. The general change trend can be divided into four stages according to morphology: δ=0, δ∈(0, 0.6], δ∈(0.6, 0.99] and δ=1. The results provide a theoretical and numerical basis for the study of high-energy electron radiation from multiple perspectives, and are helpful for the accurate detection of super-strong laser parameters in practical applications.
2023, 47(1): 140-146.
doi: 10.7510/jgjs.issn.1001-3806.2023.01.022
Abstract:
In order to explore the controllable transport of micro-nano mass in 1-D materials, a method that generate thermal gradient on carbon nanocoil by focused laser rays was adopted. Micro-nano paraffin transport process along thermally-induced carbon nanocoil irradiated by focused laser rays was analyzed experimentally and theoretically. The results show that when the laser is focused on the carbon nanocoil, the micro-nano paraffin sphere can be moved from the high temperature region to the low temperature region. The paraffin transport process in a single direction or in both directions along the carbon nanocoil can be controlled by changing the position of laser radiation. The mass and distance transported along carbon nanocoil can be controlled by adjusting the laser power. When the laser current is respectively 33.0 mA, 36.0 mA, 39.0 mA, and 42.0 mA, the transport distance of the micro-nano paraffin is 0.69 μm, 1.40 μm, 2.00 μm and 2.50 μm, respectively. These results present a new method for micro-nano mass transporting controllably on 1-D materials.
In order to explore the controllable transport of micro-nano mass in 1-D materials, a method that generate thermal gradient on carbon nanocoil by focused laser rays was adopted. Micro-nano paraffin transport process along thermally-induced carbon nanocoil irradiated by focused laser rays was analyzed experimentally and theoretically. The results show that when the laser is focused on the carbon nanocoil, the micro-nano paraffin sphere can be moved from the high temperature region to the low temperature region. The paraffin transport process in a single direction or in both directions along the carbon nanocoil can be controlled by changing the position of laser radiation. The mass and distance transported along carbon nanocoil can be controlled by adjusting the laser power. When the laser current is respectively 33.0 mA, 36.0 mA, 39.0 mA, and 42.0 mA, the transport distance of the micro-nano paraffin is 0.69 μm, 1.40 μm, 2.00 μm and 2.50 μm, respectively. These results present a new method for micro-nano mass transporting controllably on 1-D materials.
