Journals >Infrared and Laser Engineering
Contents
2019
Volume: 48 Issue 7
42 Article(s)
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Detection distance computation of the space borne infrared detector for hypersonic flight vehicles
Wang Yingying, He Ping, and Meng Changliang
The operation range of spaceborne infrared detector was computed for effective detection and early warning of hypersonic flight vehicles. Considering the influence of the different transmittance of target-detector and background-detector, path thermal and dispersion, a new operation range model was given. Parameters inThe operation range of spaceborne infrared detector was computed for effective detection and early warning of hypersonic flight vehicles. Considering the influence of the different transmittance of target-detector and background-detector, path thermal and dispersion, a new operation range model was given. Parameters in the new model were the function of the wavelength and had no concern with the range. The infrared radiation characteristics computation model of X-51A′s skin, nozzle and plume were given on basis of aerodynamics, engine′s after burning theory, plume flow field and its simplified model. The infrared radiation model in the sea background was established on the influence of the environment. It′s shown from simulations that the radiation intensity and operation range in the medium wave are larger than those in the long wave and they become larger with higher velocity. And the operation range becomes smaller when considering dispersion. It′s inferred that the detecting ability is better in the medium wave and the dispersion should be considered in real detection..
Infrared and Laser Engineering
- Publication Date: Jan. 01, 1900
- Vol. 48, Issue 7, 704003 (2019)
Elimination of trailing in long-wave infrared laser target simulation
Huang Zhanhua, Chen Bohao, Liu Kun, Cai Huaiyu, and Zhang Yinxin
Target simulation is a technology that can save time and cost of weapon testing. When long- wave infrared laser was used to project light spot on the spherical screen for target simulation, a trailing of the laser spot in the moving path will be generated. Such trailing makes it difficult to keep the dot target in its Target simulation is a technology that can save time and cost of weapon testing. When long- wave infrared laser was used to project light spot on the spherical screen for target simulation, a trailing of the laser spot in the moving path will be generated. Such trailing makes it difficult to keep the dot target in its original shape. So the trailing interferes with the accuracy of the target identification. The influences of laser power, laser spot movement speed and screen material on the trailing were investigated by theoretical analysis and a series of experiments. Firstly, the higher the laser power was, the more obvious the tailing phenomenon was under the same laser spot moving speed. Secondly, the slower the laser spot moving speed was, the more obvious the tailing phenomenon was under the same laser power conditions. Finally, different materials had great differences in the absorption capacity of 10.6 μm laser. The worse the heat dissipation was under the same laser power conditions, the more obvious the tailing phenomenon was. The results show that the trailing phenomenon of temperature rise can be effectively eliminate and reduced by adjusting the laser power in real time according to the moving speed of the laser spot and using suitable materials for the screen. And the tailing phenomenon is effectively eliminated and reduced..
Infrared and Laser Engineering
- Publication Date: Jan. 01, 1900
- Vol. 48, Issue 7, 704004 (2019)
Experimental study on infrared radiation attenuation in the 8-12 μm waveband by Yellow Sea advection fog
Li Wei, Shao Limin, and Yuan Qunzhe
In order to study the detection capabilities of the new generation of shipborne infrared detection systems under sea fog conditions, the Yellow Sea sea fog was used as the experimental environment, the uncooled infrared thermal imager was used as the detector. Different infrared radiation sources were used as detectionIn order to study the detection capabilities of the new generation of shipborne infrared detection systems under sea fog conditions, the Yellow Sea sea fog was used as the experimental environment, the uncooled infrared thermal imager was used as the detector. Different infrared radiation sources were used as detection objects in different intensity sea fogs to perform imaging experiments, a quantitative study was made based on the attenuation model of infrared radiation in different conditions.The attenuation model can be divided into two categories: physical model and empirical model. The attenuation curves under different intensities of sea fog were compared and analyzed, the results of several measurements were analyzed. It is shown that in the case of light fog, the results calculated by the physical model are almost the same as the observation results; for dense sea fog, the results calculated by the empirical model are very close to the actual observations; while under the heavy sea fog conditions, the actual observation results are more closer to empirical models..
Infrared and Laser Engineering
- Publication Date: Jan. 01, 1900
- Vol. 48, Issue 7, 704005 (2019)
Research of ROIC for geostationary interferometric infrared sounder
Chu Peisong, Chen Honglei, Li Hui, and Ding Ruijun
Geostationary Interferometric Infrared Sounder(GIIRS) is an important payload of the FY-4 meteorological satellite. It is used to obtain a variety of three-dimensional information of the atmosphere.An infrared focal plane array(IRFPA) readout integrated circuit(ROIC) for GIIRS was successfully designed in this paper. TGeostationary Interferometric Infrared Sounder(GIIRS) is an important payload of the FY-4 meteorological satellite. It is used to obtain a variety of three-dimensional information of the atmosphere.An infrared focal plane array(IRFPA) readout integrated circuit(ROIC) for GIIRS was successfully designed in this paper. The circuit choosed CTIA as the input stage, and had four levels of charge capacity. The working modes is flexible, and the correlated double sampling (CDS) structure was used to reduce circuit′s output noise. The circuit was fabricated with CSMC 0.5 μm 2P3M 5 V process. The test results of the circuit have met the expectations of the design. The circuit′s output noise is lower than 0.14 mV, and dynamic range reaches 85.6 dB. The circuit has been hybridized to MWIR HgCdTe detector and the test results show that the IRFPA works normally. The IRPFA′s output noise is lower than 0.43 mV, and dynamic range is above 75.6 dB. The IRFPA meets the requirements of the GIIRS..
Infrared and Laser Engineering
- Publication Date: Jan. 01, 1900
- Vol. 48, Issue 7, 704006 (2019)
New all-weather outdoor Raman-Mie scattering lidar system used in atmospheric aerosol pollution monitoring
Teng Man, Zhuang Peng, Zhang Zhanye, Li Lu, and Yao Yawei
A new all-weather outdoor Raman-Mie scattering lidar system was developed and used in the atmospheric aerosol pollution monitoring for the continuous observation of atmospheric boundary layer, tropospheric aerosol and cloud optical characteristics. In lidar system design, this lidar system adopted the existing mature tA new all-weather outdoor Raman-Mie scattering lidar system was developed and used in the atmospheric aerosol pollution monitoring for the continuous observation of atmospheric boundary layer, tropospheric aerosol and cloud optical characteristics. In lidar system design, this lidar system adopted the existing mature technology of Mie scattering, polarization and Raman lidar remote sensing, and its structure was compact and convenient for transportation. In lidar control design, it was easy to operate with one-touch button and the system was available with manual and automatic working modes as well as network control and data transmission functions. The automatic and manual retrieval software were applied in the lidar data processing. The former can automatically process and display the observed results in real time according to the system settings, while the latter can retrieve and display the accurate observation data according to the parameters set by the user. This lidar system has achieved the requirements of production application and it can be widely used in the fields of atmospheric environment monitoring and atmospheric science..
Infrared and Laser Engineering
- Publication Date: Jan. 01, 1900
- Vol. 48, Issue 7, 706001 (2019)
Numerical simulation of femtosecond laser multi-pulse ablation of metal iron
Wang Zhen, Fu Wenjing, and Zhang Rongzhu
According to the requirements of surface microstructural manufacture, the ablation effect of ultrashort pulses on metal materials was studied. By using the double temperature equation, a multi-pulse irradiation analysis model was established. And then the temperature variations rule of single-pulse and multi-pulse ablaAccording to the requirements of surface microstructural manufacture, the ablation effect of ultrashort pulses on metal materials was studied. By using the double temperature equation, a multi-pulse irradiation analysis model was established. And then the temperature variations rule of single-pulse and multi-pulse ablation metal iron were quantitatively calculated. The results show that some key parameters, such as laser fluence, pulse width, and pulse interval, have noticeably influence on the electron/lattice temperature variation. Finally the number of pulses that needed for the material to reach the ablation threshold under different laser fluence is plotted, which provides a theoretical basis for the laser control in the process..
Infrared and Laser Engineering
- Publication Date: Jan. 01, 1900
- Vol. 48, Issue 7, 706002 (2019)
Simulation and analysis of the self-focusing phenomenon of high intensity laser systems in nonlinear medium
Li Dongdong, Zhang Pengbo, Zhang Wenwen, and She Jiangbo
Based on high intensity laser systems theory and self-focusing research, the nonlinear medium under the beam transmission process was described using the beam propagation method and ray tracing method. Besides, it was found that some ways were suitable for nonlinear medium, such as Adams method under the ray tracing meBased on high intensity laser systems theory and self-focusing research, the nonlinear medium under the beam transmission process was described using the beam propagation method and ray tracing method. Besides, it was found that some ways were suitable for nonlinear medium, such as Adams method under the ray tracing method and recovery algorithm based on gradient information of intensity distribution. Finally, the simulation results revealed the relationship between the light intensity and these factors, including lens thickness, the refractive index of medium, the lens curvature radius and the radius of the incident beam. And combined with optical design software, it not only reflected the relationship between the product of the refractive index and the light intensity and the focus position changes, but also the results of image quality intuitively through the data of spot diagram. And two kinds of main optical methods, the ray tracing method and the beam propagation method, were made for the comparative analysis. According the simulation results, it could be determined that bits of the system was easily affected by self-focusing, so the size of certain parameters could be improved, the adverse effect could be reduced and eliminated, and an optimal method which was suitable for strong laser system could be found..
Infrared and Laser Engineering
- Publication Date: Jan. 01, 1900
- Vol. 48, Issue 7, 706003 (2019)
Numerical simulation of residual stresses induced by laser shock on the circumference surface of round rod
Zhang Xingquan, Ji Kankan, Wang Huiting, Qi Xiaoli, Chen Bin, Tong Jinyu, and Fang Guangwu
The finite element method was employed to simulate the dynamic stress waves and residual stresses induced by laser impacting the cylindrical surface of round rod made of 2024 aluminum alloy. During simulation, the code ABAQUS/Explicit was firstly utilized to simulate the process of the stress wave propagation in the roThe finite element method was employed to simulate the dynamic stress waves and residual stresses induced by laser impacting the cylindrical surface of round rod made of 2024 aluminum alloy. During simulation, the code ABAQUS/Explicit was firstly utilized to simulate the process of the stress wave propagation in the rod with the diameter 16 mm, which was induced by the laser shock wave with peak value 2 GPa. Subsequently, the other code ABAQUS/Standard was used to calculate further the residual stresses distributed in the cylindrical surface of rod. Based on the simulation results, the effects of the rod diameter on the attenuation of the peak pressure of the stress wave and the residual stress distribution were investigated. Corresponding experiments were carried out to validate the calculated results as well. The results indicate that the peak pressure of the stress wave induced by the 2 GPa shock wave decreases rapidly to 250 MPa within 400 ns in the round rod with diameter 16 mm. After laser shocking, an uneven residual stresses are distributed in central region of the impacted surface, and tensile residual stresses are formed at the center, where the value of residual stresses S11 reaches 42 MPa. While compressive residual stresses are formed in other impacted areas(radius from 0.5 mm to 1.5 mm), where the compressive residual stresses S11 are roughly 250 MPa. During the propagation of the stress wave, the decay rate of its peak pressure decreases with the enlarging rod diameter, and the compressive residual stresses distributed on the cylindrical surface increase with the increasing rod diameter..
Infrared and Laser Engineering
- Publication Date: Jan. 01, 1900
- Vol. 48, Issue 7, 706004 (2019)
Calibration of LC-SLM with strip grating phase image
Wang Famin, Zhang Yunhai, Huang wei, Miao Xin, and Guo Hongwei
In order to improve calibration accuracy of the liquid crystal spatial light modulator (LC-SLM), strip grating phase image were proposed to calibrate the LC-SLM. Firstly, the relation between the phase contrast of the strip grating and the intensity of the zero-order diffraction spots was simulated based on Fourier optIn order to improve calibration accuracy of the liquid crystal spatial light modulator (LC-SLM), strip grating phase image were proposed to calibrate the LC-SLM. Firstly, the relation between the phase contrast of the strip grating and the intensity of the zero-order diffraction spots was simulated based on Fourier optics. Then the experimental optical path was set up and the strip grating phase image was loaded on the LC-SLM to measure the relation between the gray level and the intensity of the zero-order diffraction spots. Through calculation and analysis, the relationship between the gray level and the amount of phase delay was obtained. And finally, calibration LUT file of LC-SLM for 488 nm laser was also obtained. After calibration, a higher linearity of 0.996 4, and a lower calibration error of 0.224 0 rad were got. The experimental results show that, the double-helical spot generated by the complex high-order phase was basically consistent with the simulation results when the LUT was presented on LC-SLM. The results show that for a specific wavelength, LUT file can be obtained by calibration of LC-SLM by using the strip grating phase image and the beam can be modulated effectively according to the loading phase image, and the method is simpler..
Infrared and Laser Engineering
- Publication Date: Jan. 01, 1900
- Vol. 48, Issue 7, 706005 (2019)
Flow visualization technique of laser induced fluorescence in water tunnel for flow separation and vortex structure
Geng Zihai, Cai Jinsheng, and Jiang Yubiao
The purpose of the study on experiment technology of laser induced fluorescence in water tunnel is to provide a practical, intuitive, and effective method for flow visualization on separation and vortex structure. Rhodamine B was selected as the stain and fluorescence agent which matched the optical parameter and the cThe purpose of the study on experiment technology of laser induced fluorescence in water tunnel is to provide a practical, intuitive, and effective method for flow visualization on separation and vortex structure. Rhodamine B was selected as the stain and fluorescence agent which matched the optical parameter and the characteristics of green laser sheet with 532 nm wavelength in 1 m×1 m water tunnel. The study focused on the key technical problems such as the constitution and preparation method of stain and fluorescent agent, the selection of the optimum intensity of continuous laser, the matching relationship between flow velocity and the pore pressure of dyeing line and the matching relationship between camera field of view and the flow structure in the contrast of fine adjustment. The experiments were carried out to investigate the flow field around a cylinder, the wing of a transport plane model and the cargo door of a transport plane model together with the wake by means of the dedicated laser induced fluorescence experiment technology. The typical experiment results verify that the dedicated laser induced fluorescence technique is suitable for flow visualization on flow separation and vortex structure including boundary layer, spatial separation and wake field which is a promising method worthy of popularization and application..
Infrared and Laser Engineering
- Publication Date: Jan. 01, 1900
- Vol. 48, Issue 7, 706006 (2019)
Optimization method for array element distribution of fiber laser phased array
Ci Mingru, Liu Jingjiao, Han Long, Liu Jinsheng, and Lou Yan
Improving the energy concentration of the main lobe and suppressing the grating lobe are the key to the application of optical fiber laser phased array technology. In this paper, the cutting point was the reason why laser phased array was difficult to satisfy the element spacing of λ/2 and then many grating lobes were Improving the energy concentration of the main lobe and suppressing the grating lobe are the key to the application of optical fiber laser phased array technology. In this paper, the cutting point was the reason why laser phased array was difficult to satisfy the element spacing of λ/2 and then many grating lobes were produced. Considering the problem that the aperture of the phased array was enlarged by the method of suppressing the unequal-spacing grating lobe, a new idea of introducing genetic algorithm into the optimization of element distribution of optical fiber laser phased array was proposed. The main method was to propose a fitness function related to the main lobe energy concentration and the main lobe/side lobe contrast from the perspective of the maximum suppression of the lobe. The characteristic parameters of genetic algorithm were corresponded to the main parameters of fiber laser phased array. Then, taking two kinds of linear arrays as an example 20 line array element/array element interval as 3 times wavelength and 50 line array element/array element interval as 20 times wavelength, the traditional equally spaced array elements and unequal spacing, the array element distribution and the genetic algorithm optimized the array element distribution were simulated respectively. The distribution of the far-field energy, the main lobe energy concentration and the contrast between the main lobe and the maximum lobe of the fiber laser phased array were calculated and compared. The results show that the energy concentration of the main lobe is increased by 9.69% and 3.33% respectively, and the energy contrast between the main lobe and the first grating lobe is increased by 13.12% and 9% respectively. It can be seen that the phased array optimized based on genetic algorithm is expected to obtain a longer working distance under the same total power of laser emission..
Infrared and Laser Engineering
- Publication Date: Jan. 01, 1900
- Vol. 48, Issue 7, 706007 (2019)
Outdoor lidar system for measurement of ozone and aerosol profiles
Zhang Qingsong, Hou Zaihong, and Xie Chenbo
Lidars to observe ozone and aerosol vertical profile are widely used in environment monitor area recently. A new lidar system with both functions was introduced. The 532 nm and 266 nm light beam were generated separately with second and fourth harmonic generators using Nd:YAG laser oscillator. The 289 nm and 299 nm RamLidars to observe ozone and aerosol vertical profile are widely used in environment monitor area recently. A new lidar system with both functions was introduced. The 532 nm and 266 nm light beam were generated separately with second and fourth harmonic generators using Nd:YAG laser oscillator. The 289 nm and 299 nm Raman spectrums were obtained using two Raman cells based on the theory of stimulated Raman scattering, in which one was pumped with deuterium and another was pumped with hydrogen. The ozone concentration profile was retrieved by DIAL algorithm while the aerosol concentration profile was retrieved by Mie scattering algorithm. The lidar detection results agree well with that of ozone analyzer according to the horizontal scanning experiment where the maximum relative error is less than 10%. Results observed on the science island in Hefei City, Anhui province show that the detection height is 3 km in daytime and 5 km in night time for ozone while the height is 10 km in daytime and 15 km in night time for aerosol..
Infrared and Laser Engineering
- Publication Date: Jan. 01, 1900
- Vol. 48, Issue 7, 706008 (2019)
3.2 kW laser output by domestic 25/400 μm Yb-doped fiber
Wang Biao, Pang Lu, Yi Yongqing, Pan Rong, Geng Pengcheng, Ning Ding, and Liu Jun
A high power 25/400 μm ytterbium doped double-cladding fiber(YDF) with excellent beam quality was successfully fabricated by MCVD in conjunction with solution doping technology. The dopants of the silica fiber core include Yb2O3, Al2O3 and P2O5. Al2O3 could reduce the clustering of Yb3+ and increase the doping concentrA high power 25/400 μm ytterbium doped double-cladding fiber(YDF) with excellent beam quality was successfully fabricated by MCVD in conjunction with solution doping technology. The dopants of the silica fiber core include Yb2O3, Al2O3 and P2O5. Al2O3 could reduce the clustering of Yb3+ and increase the doping concentration. P2O5 was helpful to restrain photodarkening phenomenon. The core-cladding refractive index difference is 0.001 2, corresponding to the core numerical aperture of 0.06. The value of the cladding absorption is 2.1 dB/m at 976 nm. Master oscillator power amplifier configuration based on two end pump was constructed to test the Yb-doped fiber performance. In the experiment, the power of the 1 080 nm seed is 235 W, the total power of the pump power is 3 706 W. The maximum output power is 3 243 W with a slope efficiency of 81.1%. The beam quality factor β was measured to be 1.7. Stimulated Raman scattering(SRS) has not been found in the output laser spectrum. The fiber laser continues to work for one hour, the output power is stable at 3 240 W. In addition, a kind of 25/400 μm imported fiber was tested in the same experiment schematic. Comparative experimental results show that the performance of the domestic fiber is close to the imported fiber..
Infrared and Laser Engineering
- Publication Date: Jan. 01, 1900
- Vol. 48, Issue 7, 706009 (2019)
ESCV cutting method during infrared crystal single point diamond turning process
Wang Peng, Xue Dongbai, Zhang Hao, Yang Kun, Li Weihao, and Hui Changshun
Single Point Diamond Turing(SPDT) technology has been widely used in the infrared optical surface manufacturing field. However, the micro-nano texture of turned surface is influenced by the turning parameters, the infrared material properties, tip′s parameters of the diamond tools and so on. Based on the detailed analySingle Point Diamond Turing(SPDT) technology has been widely used in the infrared optical surface manufacturing field. However, the micro-nano texture of turned surface is influenced by the turning parameters, the infrared material properties, tip′s parameters of the diamond tools and so on. Based on the detailed analyses of the factors which will affect the turned surface quality during the infrared optical surface SPDT process, a new type of cutting movement that called Evenly tool marks Space and Constant linear Velocity(ESCV) cutting method was proposed for obtaining high surface quality in the paper. The principle of the ESCV method was introduced in detail, the process of cutting parameters determination of the ESCV was given out, and the curve of spindle speed and federate of the ESCV was simulated based on the cutting parameters. A CVD ZnS workpiece was turned via ESCV method, it′s best cutting linear velocity was 3.14 m/s, the Ra value of whole surface roughness was decreased from 6.4 nm to 4.1 nm before and after ESCV. The uniform quality turned surface is gained..
Infrared and Laser Engineering
- Publication Date: Jan. 01, 1900
- Vol. 48, Issue 7, 742001 (2019)
Precision molding of As2Se3 chalcogenide glass aspheric lens
Lin Changgui, Guo Xiaoyong, Wang Xianfeng, Zhang Peiqing, Liu Xueyun, Liu Yongxing, Wang Jinping, and Dai Shixun
Chalcogenide glass lens is one of the important components for novel temperature-adaptation IR optical systems. With the development of thermal imaging civil market, the demand for industrialization technology of chalcogenide glass lens is increasing rapidly. Precision molding of As2Se3 chalcogenide glass aspheric lensChalcogenide glass lens is one of the important components for novel temperature-adaptation IR optical systems. With the development of thermal imaging civil market, the demand for industrialization technology of chalcogenide glass lens is increasing rapidly. Precision molding of As2Se3 chalcogenide glass aspheric lens were studied systematically. A series of molding process parameters were investigated and optimized for As2Se3 chalcogenide lens with a diameter of Φ21 mm. Through the compensation correction of the mould, chalcogenide lens that met the design precision of PV <0.7 μm were fabricated successfully. Effect of molding on the physical properties of As2Se3 chalcogenide glass was also investigated. The results show that after molding, the density, hardness, and glass transition temperature of As2Se3 glass decrease, whereas its maximum transmittance increases. With the help of Raman spectra, the microstructural origin of these abnormal phenomena was analyzed and discussed. This work would provide data and reference for future fabrication of large-aperture aspheric chalcogenide lens..
Infrared and Laser Engineering
- Publication Date: Jan. 01, 1900
- Vol. 48, Issue 7, 742002 (2019)
Research on infrared optical properties of SiC films by pulsed laser deposition
Huang Guojun, Lu Yimin, Cheng Yong, Tian Fangtao, Mi Chaowei, and Wan Qiang
Non-hydrogen silicon carbide (SiC) films were deposited on germanium substrate by pulsed laser deposition. The effects of laser energy on the microstructure, composition and infrared optical properties of SiC films were investigated. The infrared transmittance spectrums of SiC films were measured by Fourier transform iNon-hydrogen silicon carbide (SiC) films were deposited on germanium substrate by pulsed laser deposition. The effects of laser energy on the microstructure, composition and infrared optical properties of SiC films were investigated. The infrared transmittance spectrums of SiC films were measured by Fourier transform infrared spectroscopy (FTIR). The spectroscopy analysis showed that the characteristic absorption peak of Si-C bonding was found at 785 cm-1, and the SiC films had good transmittance in the range of 4 000-1 300 cm-1. The optical constants of the SiC films were derived by fitting transmittance spectrum curves. It was found that the refractive index and the extinction coefficient of SiC films increased monotonicly with laser energies increasing in the range of 2.5-7.7 μm. The refractive index changed from 2.15 to 2.33 as laser energies increased from 400 mJ to 600 mJ. The extinction coefficient was of the order of 10-3 when laser energies were of 400 mJ and 500 mJ. This study indicates that the SiC film is an excellent optical film material between 2.5 μm to 7.7 μm..
Infrared and Laser Engineering
- Publication Date: Jan. 01, 1900
- Vol. 48, Issue 7, 742003 (2019)
Microstructure and properties of Fe0.5NiCoCrCuTi high entropy alloy coating prepared by laser cladding
Qiu Xingwu
The Fe0.5NiCoCrCuTi high entropy alloy coating was prepared by laser cladding on 40Cr steel surface. The microstructure, hardness, wear resistance and corrosion resistance of Fe0.5NiCoCrCuTi high entropy alloy were investigated by means of scanning electron microscopy and energy dispersive spectroscopy(SEM/EDS), micro/The Fe0.5NiCoCrCuTi high entropy alloy coating was prepared by laser cladding on 40Cr steel surface. The microstructure, hardness, wear resistance and corrosion resistance of Fe0.5NiCoCrCuTi high entropy alloy were investigated by means of scanning electron microscopy and energy dispersive spectroscopy(SEM/EDS), micro/Vickers hardness tester, friction and wear tester and electrochemical workstation. Experimental results show that Fe0.5NiCoCrCuTi high entropy alloy is mainly composed of coating, heat affected zone and the substrate. The coating has no pores, cracks and other defects, metallurgical bonding with substrate; the coating is mainly composed of two kinds of lamellar microstructure morphology, the grains closely arranged, fine particles are distributed on the grain surface. There is element segregation in the coating, but to a relatively small extent. Under the combined action of fine-grained strengthening, solid solution strengthening and precipitation strengthening, the Fe0.5NiCoCrCuTi coating has high hardness, the maximum surface hardness is 857 HV, about 3.3 times as much as the 40Cr steel. High hardness and fine scale precipitates provided a guarantee for the wear resistance of the coating. The corrosion resistance of Fe0.5NiCoCrCuTi high entropy alloy coating in 3.5% NaCl and 0.5 mol/L in H2SO4 solutions are excellent, compared with 304 stainless steel, the corrosion current density were decreased by 2 and 3 orders of magnitude respectively, the corrosion potential were shift toward positive direction for 0.230 V and 0.161 V respectively..
Infrared and Laser Engineering
- Publication Date: Jan. 01, 1900
- Vol. 48, Issue 7, 742004 (2019)
[in Chinese]
In-situ temperature measurement for combustion field based on wavelength modulation spectroscopy
Shao Xin
Aiming at the problems of composition complexity, low combustion efficiency and poor combustion stability of blast furnace gas, a temperature measurement method of blast furnace gas combustion field based on wavelength modulation spectroscopy(WMS) was proposed. WMS method has the characteristics of strong anti-noise abAiming at the problems of composition complexity, low combustion efficiency and poor combustion stability of blast furnace gas, a temperature measurement method of blast furnace gas combustion field based on wavelength modulation spectroscopy(WMS) was proposed. WMS method has the characteristics of strong anti-noise ability, high measurement accuracy and high sensitivity. It was suitable for temperature measurement of blast furnace gas combustion field. Based on the measurement characteristics of tunable diode laser absorption spectroscopy, H2O was taken as the target gas, and its absorption spectral lines at 1 391.67 nm and 1 397.75 nm were selected. Two target absorption lines spectra were obtained by time division multiplexing of two lasers. The temperature measurement of blackbody furnace and flat flame combustion furnace were measured respectively for the experimental verification. The results show that the proposed detection scheme has high sensitivity to the temperature range of 500-2 000 K, and the linearity of the detection results is better than 99%. The field test verified that the system can meet the application of in-situ on-line measurement of blast furnace gas temperature, which lays a foundation for subsequent combustion optimization and energy saving and emission reduction..
Infrared and Laser Engineering
- Publication Date: Jan. 01, 1900
- Vol. 48, Issue 7, 717001 (2019)
Smartphone-based Raman system for rapid detection of flammable and explosive chemicals
Li Tianshu, Yao Qifeng, Li Hong, Wang Shuai, and Dong Mingli
Due to the public safety was always threatened by the safety problems such as leakage of hazardous chemicals and explosions in public places, it was urgent to develop a portable, rapid and accurate detection device for on-site detection of hazardous chemicals. Although the existing detection devices were able to identiDue to the public safety was always threatened by the safety problems such as leakage of hazardous chemicals and explosions in public places, it was urgent to develop a portable, rapid and accurate detection device for on-site detection of hazardous chemicals. Although the existing detection devices were able to identify the samples, because of the large volume and the demand of pretreatment, they cannot be applied in on-site quick inspection. Therefore, the fusion the Raman system and smart phone were integrated to make it more convenient and easy to fast recognition hazardous chemicals on- site. The instrument adopts big aperture lens (F/2.0) replaced the concave reflector (F/4.0) in traditional reflectance spectromete and the optical collection efficiency has increased by nearly 4 times. At the same time, the volume phase holographic transmission grating (VPG) and slit coupling technology were adopted to improve the sensitivity of the system. There were ten kinds of flammable and explosive dangerous chemical samples tested by this Raman spectroscopy system, which help to realize the on-site inspection and has the advantages of rapidity, accuracy and non-destructibility. The matching coefficient between the ten dangerous chemicals and the database can reach more than 95%. It was of great significance to the future security application..
Infrared and Laser Engineering
- Publication Date: Jan. 01, 1900
- Vol. 48, Issue 7, 717002 (2019)
Research on surface roughness measurement of speckle autocorrelation method based on SLD
Jiang Lei, Liu Hengbiao, and Li Tongbao
Surface roughness measurement using the phenomenon of speckle caused by scattering of coherent or partially coherent light by rough surface was a promising online measurement technique. The speckle elongation effect of the far-field scattered field formed by the scattering of the narrowband continuous spectral beam by Surface roughness measurement using the phenomenon of speckle caused by scattering of coherent or partially coherent light by rough surface was a promising online measurement technique. The speckle elongation effect of the far-field scattered field formed by the scattering of the narrowband continuous spectral beam by random rough surface and the feasibility of applying the effect to the surface roughness measurement were studied in this paper. Theoretical and simulation studies show that the speckle elongation becomes larger as the observation point moves away from the center of the scattered field; moreover, the speckle elongation increases as the surface roughness becomes smaller at the same observation position. The experimental system with Superluminescent Diode(SLD) as the light source was constructed. The surface roughness was measured by the optical roughness index which was derived from the speckle elongation. The roughness measurement experiment was carried out on the EDM surface roughness specimen. The results show that the optical roughness index monotonically decreases as the surface roughness of the measured surface increases. Surface roughness measurement system with the narrowband continuous spectral light source has a larger measurement range than a group of light sources with discrete wavelengths..
Infrared and Laser Engineering
- Publication Date: Jan. 01, 1900
- Vol. 48, Issue 7, 717003 (2019)
Dual-parameter characterization based on all-fiber waist-enlarged-bitapers MZ cascaded PCF-FP
Zhou Kangpeng, He Wei, Zhang Wen, Liu Feng, and Zhu Lianqing
In order to meet the requirement of monitoring temperature change during the NaCl solution concentration measurement, an interferometric sensor based on Mach-Zehnder interferometer(MZI) cascaded Fabry-Perot interferometer(FPI) was proposed. The MZI was prepared by melting and splicing a single mode fiber to form a pairIn order to meet the requirement of monitoring temperature change during the NaCl solution concentration measurement, an interferometric sensor based on Mach-Zehnder interferometer(MZI) cascaded Fabry-Perot interferometer(FPI) was proposed. The MZI was prepared by melting and splicing a single mode fiber to form a pair of tapers structure with diameter of 155 ?滋m at the waist an interval of 1.5 cm and the contrast and period of the MZI was 10 dB and 29.85 nm, respectively; Then a photonic crystal fiber (PCF) was spliced to one end of the MZI, cleaving the PCF at a distance of a 176 ?滋m from the splicing position, which a FPI was formed with contrast and period of 8 dB and 5.71 nm, respectively. By selecting the characteristic wavelength shifts of MZI and FPI interference dips in the range of 1 535-1 555 nm, in the temperature range of 30-150 ℃ and NaCl solution concentration range of 0%-24%, the temperature and refractive index sensitivities were 50 pm/℃ and 9.97 nm/RIU, respectively. The linearities were both greater than 0.97; While the interference dip of FPI was insensitive to the refractive index, and its sensitivity of temperature and linearity was 8.3 pm/℃ and 0.98, respectively. Finally, the sensitivity matrix for temperature and NaCl concentration was calculated by constructing the temperature-NaCl concentration function matrix. The interferometric sensor has good sensitivity and linearity to temperature and concentration of NaCl solution, which can realize the simultaneous measurement of the mentioned parameters..
Infrared and Laser Engineering
- Publication Date: Jan. 01, 1900
- Vol. 48, Issue 7, 717004 (2019)
Spectral recovery matrices identification and experiment of Hadamard transform spectrometer based on DMD
Xu Jun, and Xie Zhengmao
A great deal of theoretical research and experimental verification has been done on the DMD spatial light modulated Hadamard transform spectrometer, but the research on this technology was still immature, many problems need to be further studied. The spatial distribution of the dispersion spectrum on the DMD was differA great deal of theoretical research and experimental verification has been done on the DMD spatial light modulated Hadamard transform spectrometer, but the research on this technology was still immature, many problems need to be further studied. The spatial distribution of the dispersion spectrum on the DMD was different because of the different spatial positions of the pixels on the image which resulted in the different encoding matrices of the dispersion spectrum of each pixel. An identification method of spectral recovery matrix was proposed by comparing the gray values of laser-coded images and combining with the changing rules of S-matrix elements. Taking the 7-order left-shift cyclic S-matrix as an example, the results of spectral recovery were verified by two imaging experiments. In the first experiment, a laser beam of 632.8 nm was directed into the spectrometer, the spectral response range of the spectrometer was 550-680 nm, and 632.8 nm within the fifth band range from 626 nm to 644 nm. Theoretically, only the fifth spectral images with a bond range of 626-644 nm was bright, and the rest of the images have no energy distribution. The actual experimental results are in agreement with the theoretical analysis. In the second experiment, the spectrometer was used to image a color butterfly model. The spectral curves of two test points were extracted from the recovered spectral images, and compared with the spectral characteristic curves obtained by radiometer. The experimental results show that the spectral curves obtained from the recovered spectral images are basically the same as the spectral characteristics curves extracted by radiometer. Two groups of spectral recovery experimental results verify the effectiveness of the proposed identification method for spectral recovery matrix..
Infrared and Laser Engineering
- Publication Date: Jan. 01, 1900
- Vol. 48, Issue 7, 717005 (2019)
A noise estimation method for characterizing EDFA amplified broadband spectrum light source
Jiang Haoqi, Zhao Dong, Chen Yongchao, and Hong Guangwei
Optical fiber amplifier is an indispensable optical device in distributed sensing system to realize ultra-long-distance, ultra-low loss transmission. The noise characteristics of amplifier have a vital impact on the overall performance of the distributed sensing system. In the differential interference distributed sensOptical fiber amplifier is an indispensable optical device in distributed sensing system to realize ultra-long-distance, ultra-low loss transmission. The noise characteristics of amplifier have a vital impact on the overall performance of the distributed sensing system. In the differential interference distributed sensing system, the broadband spectrum light source must be used, and the detection terminal must also use the wide spectrum detection, so it was of great significance to study the noise of EDFA in the broadband spectrum distributed sensing system for the improvement of the overall performance of the sensing system. The response relation of EDFA gain to the wavelength and power of the broadband spectrum light source was studied in this paper, and the gain response curve that can describe this relation was obtained. Based on this curve, an estimation method that can characterize the noise of the broadband spectrum light source amplified by EDFA was proposed, and the noise rule of EDFA amplified broadband spectrum light source was summarized..
Infrared and Laser Engineering
- Publication Date: Jan. 01, 1900
- Vol. 48, Issue 7, 717006 (2019)
Measurement and error analysis of encircled energy of cryogenic lens
Song Junru, Xing Hui, Pei Jingyang, Yang Tianyuan, and Mu Shengbo
Cryogenic lens is usually used to detect faint point targets in deep space and low temperature environment. Encircled energy is an important index for evaluating such lens. An infrared cryogenic lens with thermal unloading structure was used as the test object. A test and error analysis scheme of encircled energy of crCryogenic lens is usually used to detect faint point targets in deep space and low temperature environment. Encircled energy is an important index for evaluating such lens. An infrared cryogenic lens with thermal unloading structure was used as the test object. A test and error analysis scheme of encircled energy of cryogenic lens was designed. A point target was received after imaging by the lens and a cryogenic precision focusing technology was used to acquire data. Centroid extraction and Gaussian curve fitting and deconvolution had been applied to data processing. Encircled energy test was implemented of infrared lens at 200 K, and errors of the test system were analyzed and calibrated. Uncertainly analysis was also evaluated to improve the test accuracy. The experimental results show the test accuracy is better than 7.5%. The method can be used in engineering application..
Infrared and Laser Engineering
- Publication Date: Jan. 01, 1900
- Vol. 48, Issue 7, 717007 (2019)
[in Chinese]
Reasearch on 250 GHz sub-harmonic mixer based on GaAs Schottky diodes
Hu Haifan, Zhao Ziran, Ma Xuming, and Jiang Shoulu
In order to compare and analyze the characteristics of two kinds of structure mixer through simulation design and measurement, the 250 GHz sub-harmonic mixers of suspended microstrip-line and conventional microstrip-line were designed respectively based on the Hammer-Head filter structure, combined with three-dimensionIn order to compare and analyze the characteristics of two kinds of structure mixer through simulation design and measurement, the 250 GHz sub-harmonic mixers of suspended microstrip-line and conventional microstrip-line were designed respectively based on the Hammer-Head filter structure, combined with three-dimensional Schottky diode model and three-dimensional electromagnetic model. The results show that in the radio frequency(RF) range of 230-270 GHz, the conversion loss of single sideband converter was 8.6-12.7 dB for suspended microstrip-line mixer, while that was 8.4-11.4 dB for ordinary microstrip-line mixer with RF range of 220-260 GHz. Contrast results showed that the bandwidth of the suspended microstrip-line mixer was larger than that of the conventional microstrip-line mixer, but its flatness was worse. Finally, considering some undesirable factors introduced in the micro assembly processes, the simulation was calculated and compared with the measuring data, it was found that the results matched well..
Infrared and Laser Engineering
- Publication Date: Jan. 01, 1900
- Vol. 48, Issue 7, 722001 (2019)
FPGA implementation of the overdriving method of liquid crystal spatial light modulator
Guo Hongyang, Du Shengping, Huang Yongmei, and Fu Chengyu
In the system of the spatial light modulator, the response time of the liquid crystal under normal driving voltage is long, and the response speed of the system is slowed down. Considering these, the factors affecting the response time of the liquid crystal, the relaxation characteristics of the liquid crystal and the In the system of the spatial light modulator, the response time of the liquid crystal under normal driving voltage is long, and the response speed of the system is slowed down. Considering these, the factors affecting the response time of the liquid crystal, the relaxation characteristics of the liquid crystal and the overdrive principle of the liquid crystal were analyzed. An overdriving method of liquid crystal based on the FPGA was put forward. Among them, phase quantization, overdriving look-up table, and PWM generation were all performed by the FPGA. This method did not occupy CPU resources and can respond to CPU instructions more quickly, and further saving LCD response time in terms of hardware. Finally, the experimental optical path was built. The experimental results show that after using the overdriving method, in a modulation period and under 5 V driving voltage, the response time of the liquid crystal modulation phase rise process is shortened from 500 ms to 35 ms, and the fall response time is shortened from 300 ms to 36 ms. The rapid deflection of the phase of the liquid crystal molecules is achieved, and the response speed of the system is improved by an order of magnitude..
Infrared and Laser Engineering
- Publication Date: Jan. 01, 1900
- Vol. 48, Issue 7, 722002 (2019)
Study on the innovative protective technology for the railway tunnel doors based on the micro-structure fiber distributed sensor
Geng Ming, Liu Chen, Xu Zhijie, He Tao, Liu Daling, Zhang Junling, Wang Yongyuan, Liu Yijie, Sun Qizhen, and Liu Deming
Protective doors of railway tunnel is an important branch of the tunnel disaster prevention and rescue project and has an important influence on safety. A novel innovative protective railway tunnel door based on the micro-structure fiber distributed sensor(MFDS) was studied in this paper, which could be used for the alProtective doors of railway tunnel is an important branch of the tunnel disaster prevention and rescue project and has an important influence on safety. A novel innovative protective railway tunnel door based on the micro-structure fiber distributed sensor(MFDS) was studied in this paper, which could be used for the alarm system, the display and recording of alarm parts and alarm data, detection of operational failure and alarm signal remote transmission function. The following research results are reached: (1) the arrangement scheme of protective doors should be taken away from the center line of tunnel; (2) the partition wall of the protective door is made of beton; (3) the door should be opened in the direction of evacuation; (4) when designing the distance between the outside of protective door and central line of adjacent lines, we should consider the frame height of protective door and vehicle clearance. The research results can provide guidance for the design of protective doors for railway tunnel to a certain extent..
Infrared and Laser Engineering
- Publication Date: Jan. 01, 1900
- Vol. 48, Issue 7, 722003 (2019)
Adaptive rate polar codes for atmospheric weak turbulence channel
Zhang Han, Tu Qiaoling, Cao Yang, Li Xiaohong, and Peng Xiaofeng
To improve the decoding performance and transmission efficiency of optical communication link in atmospheric weak turbulence channel, heuristic adaptive rate polar codes were proposed. Adaptive rate polar codes were designed based on nesting property of information bits of polar codes, which could achieve fully polarizTo improve the decoding performance and transmission efficiency of optical communication link in atmospheric weak turbulence channel, heuristic adaptive rate polar codes were proposed. Adaptive rate polar codes were designed based on nesting property of information bits of polar codes, which could achieve fully polarization and good error-correcting performance in atmospheric weak turbulence channel. To adjust the code rate of adaptive rate polar codes, cyclic redundancy check(CRC) code was introduced as stop signs, which could check decoding result. Transmitting terminal sent a set of codes with gradually lower code rates, when the received codes passed CRC check, transmitting terminal stopped and the rate of such code was the largest rate which can ensure reliable transmission. Simulation results show that, compared to traditional polar codes, adaptive rate polar codes can obtain 1.7 dB to 2.3 dB coding gain at the frame error rate(FER) of 10-8 in different atmospheric turbulence intensity. Decoding latency of adaptive rate polar codes was simulated and the throughput rate of adaptive rate polar codes was calculated. The results show that adaptive rate polar codes can meet the transmission requirements of FSO in atmospheric weak turbulence channel..
Infrared and Laser Engineering
- Publication Date: Jan. 01, 1900
- Vol. 48, Issue 7, 722004 (2019)
[in Chinese]
Design of phase retardation measuring instrument for optical wave plate
Liu Weixin, Wei Zhiwei, Zhao Wenqian, and Ding Xingbu
One laser oscillating mode would split into two with an optical wave plate being inserted in the resonator. The frequency difference of splitting modes can be measured to obtain the wave plate phase retardation. Based on the principle, a measuring instrument for wave plate was designed with optical path along vertical One laser oscillating mode would split into two with an optical wave plate being inserted in the resonator. The frequency difference of splitting modes can be measured to obtain the wave plate phase retardation. Based on the principle, a measuring instrument for wave plate was designed with optical path along vertical direction, which could choose certain measuring method according to oscillating modes altered by frequency difference. The half-cavity laser, the detection of laser intensity and frequency difference, the controlling program were described in detail. In order to automatically measure wave plate with high precision, the instrument utilized the equal intensity point of two orthogonally polarized lights as working point, and compensated the systematic errors from initial phase retardation and slightly tilted wave plate. In testing experiments, the instrument can automatically discriminate and measure arbitrary retardance wave plates. The measurements show standard deviation of about 0.01° and uncertainty of 0.03° (less than λ/10 000) as to a multi-order quartz wave plate. The instrument has traceability and only the frequency difference of laser modes is acquired in measurement..
Infrared and Laser Engineering
- Publication Date: Jan. 01, 1900
- Vol. 48, Issue 7, 718001 (2019)
Piecewise linear calibration of Fourier spectral measurement system responsivity based on the high temperature blackbody
Song Xuyao, Duanmu Qingduo, Dong Wei, Li Zhibin, Lu Xiaofeng, and Yuan Zundong
The calibration of the spectral responsivity of Fourier transform infrared(FTIR) spectrometer is the basis for accurate spectrum measurement. The spectral responsivity of FTIR spectrometer measurement system with high temperature blackbody infrared radiation characteristics, established at National Institute of MetroloThe calibration of the spectral responsivity of Fourier transform infrared(FTIR) spectrometer is the basis for accurate spectrum measurement. The spectral responsivity of FTIR spectrometer measurement system with high temperature blackbody infrared radiation characteristics, established at National Institute of Metrology, China(NIM), was calibrated based on piecewise linear calibration via the ThermoGage HT9500 high temperature reference blackbody furnace from NIM. A calculation model of the spectral responsivity calibration of FTIR measurement system was established and described. The infrared spectrum of the blackbody radiation source was measured in the temperature range of 1 273-1 973 K in the wavelength range of 1-14 μm. The results indicate that the method of piecewise linear calibration is practicable. The measured infrared spectrum in the temperature range of 1 373-1 873 K in the wavelength range of 1-14 μm was compared with the calculation which showed the signal divergence was less than 1%. The calculated temperature obtained by inverse calculation in this temperature region was compared with the actual temperature which showed the temperature divergence was less than 0.45%..
Infrared and Laser Engineering
- Publication Date: Jan. 01, 1900
- Vol. 48, Issue 7, 718002 (2019)
Design of continuous zoom medium-wave infrared spectral imaging system based on offner scheme
Liu Zhiying, Gao Liuxu, and Huang Yunhan
In order to adapt to the application requirements of different field of view spectrometers, a continuous zoom medium-wave infrared spectrum imaging system based on offner scheme was designed. The front zoom system to achieve continuous zoom in the range of 60-300 mm was introduced in the system, and a grating-type offnIn order to adapt to the application requirements of different field of view spectrometers, a continuous zoom medium-wave infrared spectrum imaging system based on offner scheme was designed. The front zoom system to achieve continuous zoom in the range of 60-300 mm was introduced in the system, and a grating-type offner concentric structure was used for spectral splitting and imaging. The working band was 3-5 μm, the cooled medium-wave infrared detector was used, the F#=4.0 in this system. According to the object image exchange principle and the power distribution principle, the initial structure of the front zoom system and the relay system were calculated, and the zemax software was used to optimize each subsystem to meet the design parameters. The modulation transfer function of the final continuous zoom medium-wave infrared spectrum imaging system based on offner scheme was close to the diffraction limit at a spatial frequency of 33 lp/mm, and the root mean square radius of the spot was smaller than one pixel. The design results show that the system structure is simple, and the image quality is good and meets the design indicator requirements at each focal length position and each spectral segment..
Infrared and Laser Engineering
- Publication Date: Jan. 01, 1900
- Vol. 48, Issue 7, 718003 (2019)
Back support structure design of mirror of space remote sensor
Wang Kejun, Dong Jihong, Zhou Pingwei, Wang Xiaoyu, and Jiang Ping
In view of the functional requirements of high surface shape error accuracy, high reliability and high stability of mirror support for space remote sensor, a three-point back support structure applied in the mirror support in the field of space was designed, the back support structure included taper sleeve, flexible seIn view of the functional requirements of high surface shape error accuracy, high reliability and high stability of mirror support for space remote sensor, a three-point back support structure applied in the mirror support in the field of space was designed, the back support structure included taper sleeve, flexible segment and adjusting pad. The in-depth study was done about support principle and engineering realization of the three-point back support structure. The error source which caused the variation of surface shape error of the three-point back supporting mirror component was summarized, the theory of surface shape variation caused by various error sources was studied, and the corresponding design of the supporting structure was carried out to alleviate the variation of the surface shape error of the mirror caused by various error sources. Firstly, the static and dynamic simulation of the design results were carried out by means of finite element analysis, then the assembled and processed mirror assembly was tested. The results show that the surface shape error of mirror with the three-points support structure is better than λ/60(λ=632.8 nm), the rigid body displacement of mirror is smaller than 0.01 mm, the dip angle is smaller than 2″, the mass of the mirror component is smaller than 4.5 kg. The component has a reasonable distribution of modal, the fundamental frequency is 254 Hz, which is higher than the requirement of 120 Hz. The maximum magnification rate of the mirror assembly under sine vibration and random vibration is 1.73 times, and the maximum stress under sine vibration and random vibration is 369 MPa, far lower than the yield limit of the selected material..
Infrared and Laser Engineering
- Publication Date: Jan. 01, 1900
- Vol. 48, Issue 7, 718004 (2019)
Lens design of star sensor with large relative aperture and wide spectral range
Meng Xiangyue, Wang Yang, Zhang Lei, Fu Yuegang, and Gu Zhiyuan
In order to improve the relative aperture of the star sensor and broaden the spectral range of the detection, the detector sensitivity calculation model was applied to determine the parameters of the optical lens in a star sensor, then an optical lens based on satellite platform was designed. The lens was composed of 7In order to improve the relative aperture of the star sensor and broaden the spectral range of the detection, the detector sensitivity calculation model was applied to determine the parameters of the optical lens in a star sensor, then an optical lens based on satellite platform was designed. The lens was composed of 7 spherical lenses, with the spectral region of 500-800 nm, the focal length of 50 mm, the relative aperture of 1/1.25, the field of view(FOV) of 8.45°×8.45°, and the total length was 83.33 mm. This lens used the telecentric structure in the image to reduce measurement errors caused by image defocus and other factors. After the optimization, the lens distortion was less than 0.5%, the center of mass color deviation was controlled within ±2 ?滋m, and the diffraction encircled energy (within 3×3 pixel) was greater than 80%, the maximum magnification chromatic aberration was -0.073 ?滋m, the dispersion spot energy concentration of all the fields of view was almost the same. In different temperature environments, the small change in focal length of the system verified the athermalization. The optical lens had good image quality..
Infrared and Laser Engineering
- Publication Date: Jan. 01, 1900
- Vol. 48, Issue 7, 718005 (2019)
[in Chinese]
Numerical study of multiscale multigroup wide band k-distribution model for emote infrared imaging of marine ejector exhaust system
Li Yuxuan, Wang Qiang, and Hu Haiyang
To solve the problem that existing k distribution model is not suitable for calculating the radiation characteristics of gases with drastic changes in temperature and the proportion of participating components, a multiscale multigroup wide band k-distribution model(MSMGWB) was established. The spectral absorption coeffTo solve the problem that existing k distribution model is not suitable for calculating the radiation characteristics of gases with drastic changes in temperature and the proportion of participating components, a multiscale multigroup wide band k-distribution model(MSMGWB) was established. The spectral absorption coefficient grouping of MSMGWB model was optimized according to the thermodynamic parameters of high temperature gas and ambient air for the calculation of remote sensing thermal image of exhaust system of marine turbine engine. The calculation results of a series of one-dimensional gas radiation transmission examples show that when the temperature of high temperature gas and low temperature air and the mole ratio of water vapor, carbon dioxide and carbon monoxide are greatly different, the prediction accuracy of the multiscale multigroup wide band k-distribution model for the 3-5 micron wave band gas radiation transmission characteristics is much higher than that of the original wide band k-distribution model and narrow band model, and it maintains good compatibility with the solid wall. Finally, the flow field, solid temperature field and close-range and long-range infrared images of exhaust system of marine turbine engine under different relative wind speeds were studied. The results show that the effects of gas gravity and carbon monoxide on infrared images under the 3-5 ?滋m band cannot be ignored..
Infrared and Laser Engineering
- Publication Date: Jan. 01, 1900
- Vol. 48, Issue 7, 704001 (2019)
Extinction characteristics of biological aggregated particles in the far infrared band
Chen Xi, Hu Yihua, Gu Youlin, Zhao Xinying, and Wang Xinyu
The spectral reflectance of biological material FANS 233D in the band of 2.5-15 μm was recorded by using infrared microscopic spectrometer. Based on Kramersd-Kronig(K-K) relationship, the complex refractive index of the material in 8-14 μm was calculated. A cluster-cluster model was used to stimulate the spatial structThe spectral reflectance of biological material FANS 233D in the band of 2.5-15 μm was recorded by using infrared microscopic spectrometer. Based on Kramersd-Kronig(K-K) relationship, the complex refractive index of the material in 8-14 μm was calculated. A cluster-cluster model was used to stimulate the spatial structure of FANS 233D biological aggregated particles with different fractal dimensions. The extinction parameters of biological aggregated particles with fractal dimension in the far infrared band were calculated by discrete dipole approximation and the mass extinction coefficient was calculated under different conditions. The results indicate that the larger the fractal dimension of biological aggregated particles with the same original particle, the better the extinction performance in the far infrared band. When the value of original particle number, fractal dimension, mass density was 50, 2.00, 1 120 kg/m3 respectively, the mass extinction coefficient in the 8-14 μm band can reach 2.262 m2/g. The mass extinction coefficient of the aggregated particles increases slowly with the increase of the original particle radius..
Infrared and Laser Engineering
- Publication Date: Jan. 01, 1900
- Vol. 48, Issue 7, 704002 (2019)
[in Chinese]
Optical phase conjugation (OPC) for focusing light through/inside biological tissue
Chengmingyue Li
Optical phase conjugation(OPC) is a technique that generates a light field with reversed wavefront and identical amplitude distribution as the incident light. It has a unique feature of suppressing the aberration of incident beam induced by inhomogeneous or disturbing medium. Although this technique has been extensivelOptical phase conjugation(OPC) is a technique that generates a light field with reversed wavefront and identical amplitude distribution as the incident light. It has a unique feature of suppressing the aberration of incident beam induced by inhomogeneous or disturbing medium. Although this technique has been extensively studied since the 1970s, it has become more attractive because of unprecedented achievements and prospective potentials in biomedical applications. OPC-based techniques have been successfully utilized to form a focus through/inside highly scattered biological samples. It opens a new avenue by significantly enhancing the light delivery in biological tissue for high-resolution imaging, diagnosis and treatment of medical diseases. In order to provide insight into its further development, recent progress of OPC techniques for focusing light through/inside biological tissue was summarized..
Infrared and Laser Engineering
- Publication Date: Jan. 01, 1900
- Vol. 48, Issue 7, 702001 (2019)
Curved holography based on Ω-shaped conformal metasurfaces
Han Na, Huang Lingling, Lin Zemeng, and Wang Yongtian
Conformal metasurfaces can break the restrictions between the geometry of an object and its optical functionality and allow the scattering wavefronts to be modulated willingly. Here, it is demonstrated that adaptive conformal metasurfaces is composed of achiral mirror symmetry Ω-shaped gold antenna, which can be integrConformal metasurfaces can break the restrictions between the geometry of an object and its optical functionality and allow the scattering wavefronts to be modulated willingly. Here, it is demonstrated that adaptive conformal metasurfaces is composed of achiral mirror symmetry Ω-shaped gold antenna, which can be integrated on arbitrary substrate to achieve curved holography in the visible range (λ=450 nm). The underline modulation scheme of conformal metasurface relies on the Pancharatnam-Berry phase, which can be continuously controlled in each subwavelength unit cell by rotating the orientation angle of the antenna. Such conformal metasurfaces decorated on curved topological objects can be employed in various practical application such as curved lens focusing, invisibility cloaking, and security printing technologies..
Infrared and Laser Engineering
- Publication Date: Jan. 01, 1900
- Vol. 48, Issue 7, 702002 (2019)
[in Chinese]
Transmission properties of Au-dielectric-Au multilayer films with rectangular hole arrays
Han Jing, Shao Yabin, Wang Jun, Zhao Xin, and Gao Yachen
The extraordinary optical transmission properties of periodic subwavelength hole arrays were of great significance in the design of subwavelength optoelectronic devices. The periodic hole array structure on two or more layers can lead to new optical properties due to the interaction of the electromagnetic fields betweeThe extraordinary optical transmission properties of periodic subwavelength hole arrays were of great significance in the design of subwavelength optoelectronic devices. The periodic hole array structure on two or more layers can lead to new optical properties due to the interaction of the electromagnetic fields between the layers. The transmission properties of a rectangular nanohole array in Au-dielectric-Au multilayer films were simulated using the finite-difference time-domain method. The results show that there are multiple transmission peaks in the transmission spectra of the structure in the near-infrared region.The number, position and intensity of the transmission peak can be controlled by changing the geometrical parameters of the structure and the dielectric film of material. The influences of the thickness and refractive index of the dielectric film, the period of the hole arrays, the length of the rectangular hole on the transmission spectrum were analyzed in detail. It provides a reference for designing multi-wavelength control devices using multiple surface plasmon resonances..
Infrared and Laser Engineering
- Publication Date: Jan. 01, 1900
- Vol. 48, Issue 7, 721001 (2019)
[in Chinese]
Parameter estimation of circular SAR 3-D imaging method based on the minimum energy criterion
Wang Baoping, Ma Jianjun, Zhang Yan, and Fang Yang
In order to solve the problem of low efficiency and poor accuracy of the 3-D imaging algorithm using parameter estimation in the imaging mode of circular synthetic aperture radar, a 3-D imaging algorithm of parameter estimation circular SAR based on the minimum energy criterion was proposed. Firstly, the imaging scene In order to solve the problem of low efficiency and poor accuracy of the 3-D imaging algorithm using parameter estimation in the imaging mode of circular synthetic aperture radar, a 3-D imaging algorithm of parameter estimation circular SAR based on the minimum energy criterion was proposed. Firstly, the imaging scene was divided into a rough mesh with the algorithm, the method of parameter estimation was used to get the rough position of the target. Secondly, the minimum energy criterion and the fine grid method were used to get the accurate 3-D position and scattering intensity coefficient of the target. Finally, the CLEAN technology was used to eliminate the impact of estimated points and realize 3-D imaging of the scene. The simulation results show that the proposed imaging method can effectively carry out 3-D imaging of the objects under circular observation. Meanwhile, compared with the traditional algorithm, it solves the problems of low efficiency and inaccurate target estimation of the traditional algorithm, and verifies the effectiveness of the proposed algorithm..
Infrared and Laser Engineering
- Publication Date: Jan. 01, 1900
- Vol. 48, Issue 7, 726001 (2019)
Laser reflection tomography target reconstruction algorithm based on algebraic iteration
Yang Biao, and Hu Yihua
In order to improve the image quality of laser reflection tomography target reconstruction, an iterative reconstruction algorithm commonly used in CT imaging was introduced in the image reconstruction process of laser reflex tomography. Then, the performance characteristics of direct backprojection algorithm, R-L and SIn order to improve the image quality of laser reflection tomography target reconstruction, an iterative reconstruction algorithm commonly used in CT imaging was introduced in the image reconstruction process of laser reflex tomography. Then, the performance characteristics of direct backprojection algorithm, R-L and S-L filtered backprojection algorithm and iterative reconstruction algorithm in image reconstruction were analyzed. Finally, simulations and field experiments were conducted. The results show that the filtered backprojection algorithm has a significant improvement over the direct backprojection algorithm in reducing errors and suppressing noise. In addition, compared with the backprojection algorithm, algebraic iterative reconstruction algorithm shows better reconstruction quality and has stronger noise suppression performance..
Infrared and Laser Engineering
- Publication Date: Jan. 01, 1900
- Vol. 48, Issue 7, 726002 (2019)
Successive spectral unmixing for hyperspectral images based on L1/2 regularization
Tang Yi, Nian Yongjian, He Mi, Wang Qiannan, and Xu Ke
Due to the high mixed degree of hyperspectral remote sensing images, the basic component extracted by the traditional Nonnegative Matrix Underapproximation(NMU) algorithm is still "impurity", moreover, it is susceptible to noise. To overcome the above shortcomings, a method named L1/2-regularized soft-threshoDue to the high mixed degree of hyperspectral remote sensing images, the basic component extracted by the traditional Nonnegative Matrix Underapproximation(NMU) algorithm is still "impurity", moreover, it is susceptible to noise. To overcome the above shortcomings, a method named L1/2-regularized soft-thresholding NMU for hyperspectral unmixing was proposed. Firstly, the L1/2 regularization term for abundance was introduced to improve the distinguishing ability, which can further improve the purity of the extracted components. Secondly, the soft-threshold penalty function was introduced to replace the residual nonnegative constraint in NMU. By adjusting the penalty factor, the number of non-negative elements could be well controlled, which could improve the anti-noise ability. Experimental results on the simulational and real datasets show that the proposed algorithm can obtain better separation results even under noisy conditions..
Infrared and Laser Engineering
- Publication Date: Jan. 01, 1900
- Vol. 48, Issue 7, 726003 (2019)
Using multi-source satellite imagery data to monitor cyanobacterial blooms of ChaohuLake
Zhang Dongyan, Yin Xun, She Bao, Ding Yuwan, Liang Dong, Huang Linsheng, Zhao Jinling, and Gao Yunbing
Dynamically, accurately monitoring of cyanobacteria blooms in the inland lakes can provide a basis for evaluating the control effects of polluted water bodies, moreover optimize and adjust prevention policies for water conservancy and environmental protection departments. In this paper, Chaohu Lake was chosen as there Dynamically, accurately monitoring of cyanobacteria blooms in the inland lakes can provide a basis for evaluating the control effects of polluted water bodies, moreover optimize and adjust prevention policies for water conservancy and environmental protection departments. In this paper, Chaohu Lake was chosen as there search object, the satellite imagery data with different spatial resolution such as the Landsat TM/OLI, HJ-1B CCD/IRS and NPP-VIIRS, were used to extract the Chaohu water body by the Normalized Difference Water Index(NDWI). And then the areas of cyanobacterial blooms in the Chaohu Lake were calculated using the Normalized Difference Vegetation Index(NDVI) and the Floating Algae Index (FAI). Further, the extracted cyanobacterial areas using the different methods were compared and analyzed, and the monitoring effects and applicability were evaluated by the spatial and temporal characteristics for Landsat, HJ-1B and VIIRS imagery data. Additionally, the effects of different meteorological factors on the cyanobacterial blooms were also analyzed. The research results displayed that comparing with the NDVI index, the FAI index calculated from the Landsat, HJ-1B and VIIRS imagery data can reduce the effect of thin cloud on the extraction of cyanobacterial blooms, and improve the recognition ability of cyanobacterial blooms and extents. Secondly, the temperature and sunshine duration of meteorological factors aggravate the severity of cyanobacterial blooms, and the rainfall plays a certain role in inhibiting the outbreak of cyanobacterial blooms. In summary, this study introduced the VIIRS imagery data to study the cyanobacterial blooms in Chaohu Lake, and used the FAI index to reduce the influence of thin cloud on the extraction precision of cyanobacterial blooms. These results show that multi-source satellite imagery data can provide the important method support for the development of dynamically monitoring system on cyanobacterial blooms. This is useful to promote the satellite remote sensing technology to improve the "river system" and "lake system" in Anhui Province..
Infrared and Laser Engineering
- Publication Date: Jan. 01, 1900
- Vol. 48, Issue 7, 726004 (2019)
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