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Scattering|51 Article(s)
Optical Scattering Properties of Particles and Group Particles with Core-Shell Structure
Qianjun Mao, and Kaiyan Yang
To explore the scattering characteristics of aerosol particles in the near infrared band, the optical scattering characteristics of two hypothetical structures having mixed core-shell particles and the same aerosol particles in black carbon and sulfate aerosols are investigated by using discrete dipole approximation. A core-shell particle model with black carbon as the core and ammonium sulfate as the shell is constructed to simulate the extinction efficiency factor, scattering efficiency factor, absorption efficiency factor, asymmetry factor, and single scattering albedo of the particles at several incident wavelengths (875, 1020, 1640, and 2000 nm) in specific incident directions with varied effective particle sizes. The numerical results show that the extinction, scattering, and absorption efficiency factors of mononuclear shell particle, two-core cluster particle, and three-core cluster particle initially increase and then decrease with an increasing effective particle size at the same incident wavelength. In addition, the differences in the scattering and extinction efficiency factors of the three particles are less than 10%. With an increase in the number of nuclear particles, the radius of the particle structure increases, and the peak of the efficiency factor shifts backward. At the four different wavelengths, the asymmetry factor of the multi-nucleated cluster particles is 0.1777, 0.1960, 0.2900, and 0.3131 larger than that of the mononuclear shell particles on average, and the average difference between the asymmetry factors of the two types of multi-nucleated particles is 0.096. At the same effective particle size, the single scattering albedo of mononuclear shell particles is higher than that of multi-core particles; the larger the wavelength, the more distinct is the difference. The results are useful for further analyses of the optical scattering characteristics of complex atmospheric aerosol particles and monitoring of pollutants and climate. To explore the scattering characteristics of aerosol particles in the near infrared band, the optical scattering characteristics of two hypothetical structures having mixed core-shell particles and the same aerosol particles in black carbon and sulfate aerosols are investigated by using discrete dipole approximation. A core-shell particle model with black carbon as the core and ammonium sulfate as the shell is constructed to simulate the extinction efficiency factor, scattering efficiency factor, absorption efficiency factor, asymmetry factor, and single scattering albedo of the particles at several incident wavelengths (875, 1020, 1640, and 2000 nm) in specific incident directions with varied effective particle sizes. The numerical results show that the extinction, scattering, and absorption efficiency factors of mononuclear shell particle, two-core cluster particle, and three-core cluster particle initially increase and then decrease with an increasing effective particle size at the same incident wavelength. In addition, the differences in the scattering and extinction efficiency factors of the three particles are less than 10%. With an increase in the number of nuclear particles, the radius of the particle structure increases, and the peak of the efficiency factor shifts backward. At the four different wavelengths, the asymmetry factor of the multi-nucleated cluster particles is 0.1777, 0.1960, 0.2900, and 0.3131 larger than that of the mononuclear shell particles on average, and the average difference between the asymmetry factors of the two types of multi-nucleated particles is 0.096. At the same effective particle size, the single scattering albedo of mononuclear shell particles is higher than that of multi-core particles; the larger the wavelength, the more distinct is the difference. The results are useful for further analyses of the optical scattering characteristics of complex atmospheric aerosol particles and monitoring of pollutants and climate.
Laser & Optoelectronics Progress
- Publication Date: Mar. 10, 2024
- Vol. 61, Issue 5, 0529001 (2024)
Research on Performance of Wireless Ultraviolet Communication Interference Link
Taifei Zhao, Qianwen Ma, and Yi Zhao
When solar-blind wireless ultraviolet light system is used to communicate, if multiple links are active at once, the active links will overlap with effective scatters in space, resulting in mutual interference and a reduction in communication performance. This study develops a method for simulating the wireless ultraviolet non-line-of-sight communication scattering channel and validates the model's accuracy by comparing it to a common interference model. And this model is used to simulate the co-planar interference, non-co-planar interference, and the link interference model under non-co-planar and height difference interference in wireless ultraviolet communication. The results show that the main factors affecting the bit error rate of the channel are the location of the interference terminal and the size of the effective scatterer, in the case of non-co-planar and height difference interference, the inter-link interference can be reduced by adjusting the transmitter elevation angle, and the performance of the communication system can be improved. When solar-blind wireless ultraviolet light system is used to communicate, if multiple links are active at once, the active links will overlap with effective scatters in space, resulting in mutual interference and a reduction in communication performance. This study develops a method for simulating the wireless ultraviolet non-line-of-sight communication scattering channel and validates the model's accuracy by comparing it to a common interference model. And this model is used to simulate the co-planar interference, non-co-planar interference, and the link interference model under non-co-planar and height difference interference in wireless ultraviolet communication. The results show that the main factors affecting the bit error rate of the channel are the location of the interference terminal and the size of the effective scatterer, in the case of non-co-planar and height difference interference, the inter-link interference can be reduced by adjusting the transmitter elevation angle, and the performance of the communication system can be improved.
Laser & Optoelectronics Progress
- Publication Date: May. 10, 2023
- Vol. 60, Issue 9, 0929001 (2023)
Upper Limit Analysis of Measurable Particle Size by Interferometric Particle Imaging Technology
Chunshuai Fu, Lü Qieni, Hao Liu, and Taiyu Liu
This study experimentally investigates the maximum measurable particle size of interferometric particle imaging (IPI). The maximum measurable particle size for IPI was examined in relation to the effect of object distance variation brought on by several object planes in the same field of vision. The IPI experimental system irradiated by a single beam was built to measure the polystyrene mixed particle fields with particle diameter of 51 μm and 110 μm, and the maximum measurable particle size in different collection areas in the same field of view was analyzed. The outcomes of the experiment demonstrate that the spatial relationship between the objects in the experimental system has an impact on the maximum quantifiable particle size of IPI technology. The maximum quantifiable particle size of various acquisition areas within the same field of view varies for an experimental system with fixed parameters. This study experimentally investigates the maximum measurable particle size of interferometric particle imaging (IPI). The maximum measurable particle size for IPI was examined in relation to the effect of object distance variation brought on by several object planes in the same field of vision. The IPI experimental system irradiated by a single beam was built to measure the polystyrene mixed particle fields with particle diameter of 51 μm and 110 μm, and the maximum measurable particle size in different collection areas in the same field of view was analyzed. The outcomes of the experiment demonstrate that the spatial relationship between the objects in the experimental system has an impact on the maximum quantifiable particle size of IPI technology. The maximum quantifiable particle size of various acquisition areas within the same field of view varies for an experimental system with fixed parameters.
Laser & Optoelectronics Progress
- Publication Date: Mar. 25, 2023
- Vol. 60, Issue 6, 0629001 (2023)
Numerical Analysis of Mueller Matrix for Random Rough Surfaces
Lu Yang, Qian Tong, Zhiyin Zhou, Siyuan He, and Zhe Song
The Mueller matrix describes the influence of an object on the polarization of optical waves. It has various information about the object surface. In this paper, the scattering field and the scattering Mueller matrix of two-dimensional random rough surfaces are analyzed using the Kirchhoff approximation method. The scattering Mueller matrices of copper, iron, nickel, glass, and lithium niobate are numerically simulated using the incidence angle, and the relative roughness is changed. With the increase of the incident angle, the m01, m10, m22, and m33 parameters of metals and dielectrics vary by less than 30% and greater than 80%, respectively. The m00, m11, m22, and m33 parameters of metals and dielectrics vary by more than 60% and less than 20%, respectively. Further, the m23 and m32 parameters of metals are increased as the incident angle increases, and are decreased as the relative roughness increases, whereas the m23 and m32 parameters of the dielectric are always 0. The differences can be used for identifying metal and dielectric and provide some reference to the measurement of object surface roughness. The Mueller matrix describes the influence of an object on the polarization of optical waves. It has various information about the object surface. In this paper, the scattering field and the scattering Mueller matrix of two-dimensional random rough surfaces are analyzed using the Kirchhoff approximation method. The scattering Mueller matrices of copper, iron, nickel, glass, and lithium niobate are numerically simulated using the incidence angle, and the relative roughness is changed. With the increase of the incident angle, the m01, m10, m22, and m33 parameters of metals and dielectrics vary by less than 30% and greater than 80%, respectively. The m00, m11, m22, and m33 parameters of metals and dielectrics vary by more than 60% and less than 20%, respectively. Further, the m23 and m32 parameters of metals are increased as the incident angle increases, and are decreased as the relative roughness increases, whereas the m23 and m32 parameters of the dielectric are always 0. The differences can be used for identifying metal and dielectric and provide some reference to the measurement of object surface roughness.
Laser & Optoelectronics Progress
- Publication Date: Mar. 10, 2023
- Vol. 60, Issue 5, 0529002 (2023)
Experimental Measurement of Solar Radiation Energy Flux Distribution on Curved Surfaces
Guilong Dai, Ying Zhuang, Xiaoyu Wang, and Yu Zhuang
In order to measure the concentrated solar radiation flux distribution of curved surface absorbers, based on segmented-jointed approaches, a measurement method for the solar flux density distribution on the curved surfaces is proposed according to the characteristics of the surface radiation transfer. By dividing and extracting the hemispherical shell, a hollow water-cooled strip spherical arc Lambertian target is designed and processed. Using image space coordinate transformation and surface radiation transfer calculation, the entire spherical shell surface is obtained by splicing multiple sub-images. The measurement method is experimentally verified on an indoor solar simulator using a CCD camera to assemble a test system. The results show that the uncertainty of this method is 5.12%. The distribution of solar flux density along the circumferential and zenith angles of the hemispherical surface is uneven, and the peak energy flux density appears at the outer edge of the surface vertex, which is significantly different from the focal plane energy flux density distribution. In order to measure the concentrated solar radiation flux distribution of curved surface absorbers, based on segmented-jointed approaches, a measurement method for the solar flux density distribution on the curved surfaces is proposed according to the characteristics of the surface radiation transfer. By dividing and extracting the hemispherical shell, a hollow water-cooled strip spherical arc Lambertian target is designed and processed. Using image space coordinate transformation and surface radiation transfer calculation, the entire spherical shell surface is obtained by splicing multiple sub-images. The measurement method is experimentally verified on an indoor solar simulator using a CCD camera to assemble a test system. The results show that the uncertainty of this method is 5.12%. The distribution of solar flux density along the circumferential and zenith angles of the hemispherical surface is uneven, and the peak energy flux density appears at the outer edge of the surface vertex, which is significantly different from the focal plane energy flux density distribution.
Laser & Optoelectronics Progress
- Publication Date: Mar. 10, 2023
- Vol. 60, Issue 5, 0529001 (2023)
Development of Experimental System for Liquid Thermal Diffusion by Dynamic Light Scattering Method
Yirui Wang, Guanjia Zhao, Jianguo Yin, and Suxia Ma
Based on the principle of dynamic light scattering, this paper develops a set of dynamic light scattering apparatus which can measure the thermal diffusivity. The experimental system includes scattering light path, pressure vessel, temperature control system, and data acquisition system. The optical fiber is introduced into the dynamic light scattering system as a probe, which reduces the experimental system to 1/3 of the similar system. In this paper, the reference fluid n-hexane was used to test the accuracy of the experimental system. The thermal diffusivity obtained from the experiment was fitted into a polynomial equation with a maximum deviation of 0.19%, an average absolute deviation of 0.11%, and the maximum deviation between experimental and literature values was 3%. After uncertainty analysis, the uncertainty of liquid thermal diffusivity measured by the newly developed dynamic light scattering experimental system is 2% (k=2). Based on the principle of dynamic light scattering, this paper develops a set of dynamic light scattering apparatus which can measure the thermal diffusivity. The experimental system includes scattering light path, pressure vessel, temperature control system, and data acquisition system. The optical fiber is introduced into the dynamic light scattering system as a probe, which reduces the experimental system to 1/3 of the similar system. In this paper, the reference fluid n-hexane was used to test the accuracy of the experimental system. The thermal diffusivity obtained from the experiment was fitted into a polynomial equation with a maximum deviation of 0.19%, an average absolute deviation of 0.11%, and the maximum deviation between experimental and literature values was 3%. After uncertainty analysis, the uncertainty of liquid thermal diffusivity measured by the newly developed dynamic light scattering experimental system is 2% (k=2).
Laser & Optoelectronics Progress
- Publication Date: Jan. 10, 2023
- Vol. 60, Issue 1, 0129002 (2023)
Influence of Different Structures of Capillary Cell on Electric Field Intensity in Detection Area
Wenquan Qiu, Wei Liu, Hongyan Jia, Tiantian Qi, Jin Shen, and Yajing Wang
If the electric field intensity in the detection area of the capillary cell is non-uniform, a slight change in the detection position will result in a large change in the electric field intensity, which in turn will reduce the accuracy of the zeta potential measurement results. In order to improve the accuracy and repeatability of the zeta potential measurement results, an electric field simulation was carried out for capillary cells with different electrode sizes and cell structures. By analyzing the effect of electrode size and capillary cell structure on electric field intensity uniformity, the optimal capillary cell structure was obtained. If the electric field intensity in the detection area of the capillary cell is non-uniform, a slight change in the detection position will result in a large change in the electric field intensity, which in turn will reduce the accuracy of the zeta potential measurement results. In order to improve the accuracy and repeatability of the zeta potential measurement results, an electric field simulation was carried out for capillary cells with different electrode sizes and cell structures. By analyzing the effect of electrode size and capillary cell structure on electric field intensity uniformity, the optimal capillary cell structure was obtained.
Laser & Optoelectronics Progress
- Publication Date: Jan. 10, 2023
- Vol. 60, Issue 1, 0129001 (2023)
Particle Size and Concentration of Monodisperse Au-Ag Alloy Nanospheres Retrieved by Light Extinction Method
Yuxia Zheng, Tuersun Paerhatijiang, Abulaiti Remilai, Dengpan Ma, and Long Cheng
Variation of light extinction properties of monodisperse Au-Ag alloy nanospheres with particle size and wavelength are analyzed based on Mie theory. In the theoretical calculations, the dielectric function of Au-Ag alloy nanoparticles is corrected for the effect of the reduced mean free path of the free electrons in metal nanoparticles. Three fitting equations for determining particle size and concentration methods based on the extinction properties are proposed in this paper, including resonance wavelength method, dual-wavelength extinction method, and improved dual-wavelength extinction method. The results show that as long as the extinction spectrum of the particles is measured, the particle size and concentration can be retrieved by using the fitting equations. In addition, comparing the sensitivity and the particle size range of three methods are found that the resonance wavelength method is easier and faster than other methods. Variation of light extinction properties of monodisperse Au-Ag alloy nanospheres with particle size and wavelength are analyzed based on Mie theory. In the theoretical calculations, the dielectric function of Au-Ag alloy nanoparticles is corrected for the effect of the reduced mean free path of the free electrons in metal nanoparticles. Three fitting equations for determining particle size and concentration methods based on the extinction properties are proposed in this paper, including resonance wavelength method, dual-wavelength extinction method, and improved dual-wavelength extinction method. The results show that as long as the extinction spectrum of the particles is measured, the particle size and concentration can be retrieved by using the fitting equations. In addition, comparing the sensitivity and the particle size range of three methods are found that the resonance wavelength method is easier and faster than other methods.
Laser & Optoelectronics Progress
- Publication Date: Apr. 10, 2022
- Vol. 59, Issue 7, 0729001 (2022)
Lidar Slant-Range Visibility Retrieval Method Based on Effect of Multiple Scattering
Xinglong Xiong, Jie Wang, Kui Liu, and Yuzhao Ma
Aiming at the effect of multiple scattering under low visibility weather conditions, an improved method is proposed for inverting slant-range visibility based on the multiple scattering lidar equation. First, the semi-analytical Monte Carlo method is used to calculate the ratio m of multiple scattering to single scattering based on the backscattering peak fitting the scattering phase function. Second, using the Collis method, the visibility level value is obtained, and the corresponding m value is substituted into the multiple scattering lidar equation. Then, the Fernald method is used to invert the extinction coefficient and solve the slant-range visibility. Experiments were performed on the echo signals of haze and heavy rain with different visibility levels detected by lidar, and the slant-range visibility results obtained using the fitting method in this paper and the commonly used Henyey-Greenstein (HG) function method were compared. The results show that the slant-range visibility difference is 10.9% under haze conditions and 5.6% under heavy rain conditions. The proposed method improves slant-range visibility accuracy inverted by the backscattering lidar. Aiming at the effect of multiple scattering under low visibility weather conditions, an improved method is proposed for inverting slant-range visibility based on the multiple scattering lidar equation. First, the semi-analytical Monte Carlo method is used to calculate the ratio m of multiple scattering to single scattering based on the backscattering peak fitting the scattering phase function. Second, using the Collis method, the visibility level value is obtained, and the corresponding m value is substituted into the multiple scattering lidar equation. Then, the Fernald method is used to invert the extinction coefficient and solve the slant-range visibility. Experiments were performed on the echo signals of haze and heavy rain with different visibility levels detected by lidar, and the slant-range visibility results obtained using the fitting method in this paper and the commonly used Henyey-Greenstein (HG) function method were compared. The results show that the slant-range visibility difference is 10.9% under haze conditions and 5.6% under heavy rain conditions. The proposed method improves slant-range visibility accuracy inverted by the backscattering lidar.
Laser & Optoelectronics Progress
- Publication Date: Feb. 20, 2022
- Vol. 59, Issue 4, 0429001 (2022)
Particle Size Measurement of Extinction Spectrum Based on Near-Infrared Narrow Band Light Source
Xiangpeng Li, Huazhong Xiang, Gang Zheng, Minghui Chen, and Hui Yang
In this paper, a particle size measurement method based on continuous transmission extinction spectral is proposed. Based on Mie scattering theory and artificial bee colony algorithm for particle size inversion. The results show that the relative root-mean-square error (RRMSE) of particle volume frequency distribution curve is as low as 0.08% for unimodal distribution, and the RRMSE of particle volume frequency distribution curve is as low as 3.49% for bimodal distribution. Comparative experiments are conducted with the standard polystyrene latex particles numbered GBW120134, GBW120024 and GBW120041. The results show that the relative error of D50 particle size is within 10% for unimodal distribution, and the relative error of D50 particle size is within 20% for bimodal distribution. In this paper, a particle size measurement method based on continuous transmission extinction spectral is proposed. Based on Mie scattering theory and artificial bee colony algorithm for particle size inversion. The results show that the relative root-mean-square error (RRMSE) of particle volume frequency distribution curve is as low as 0.08% for unimodal distribution, and the RRMSE of particle volume frequency distribution curve is as low as 3.49% for bimodal distribution. Comparative experiments are conducted with the standard polystyrene latex particles numbered GBW120134, GBW120024 and GBW120041. The results show that the relative error of D50 particle size is within 10% for unimodal distribution, and the relative error of D50 particle size is within 20% for bimodal distribution.
Laser & Optoelectronics Progress
- Publication Date: Nov. 10, 2022
- Vol. 59, Issue 21, 2129002 (2022)
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