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Scattering|25 Article(s)
Self-calibrated global rainbow refractometry: a dual-wavelength approach
Xuecheng Wu, Haoyu Jiang, Kailin Cao, Yingchun Wu, Can Li, Gérard Gréhan, Sawitree Saengkaew, and Kefa Cen
Calibration of the relationship between the scattering angle and the CCD pixel is a key part of achieving accurate measurements of rainbow refractometry. A novel self-calibrated global rainbow refractometry system based on illumination by two lasers of different wavelengths is proposed. The angular calibration and refractive index measurement of two wavelengths can be completed simultaneously without extra measurement devices. The numerical and experimental results show the feasibility and high precision of the self-calibration method, which enables the rainbow refractometry to be implemented in a more powerful and convenient way. The self-calibrated rainbow system is successfully applied to measure the refractive indices of ethanol-water solutions with volume concentrations of 10% to 60%. Calibration of the relationship between the scattering angle and the CCD pixel is a key part of achieving accurate measurements of rainbow refractometry. A novel self-calibrated global rainbow refractometry system based on illumination by two lasers of different wavelengths is proposed. The angular calibration and refractive index measurement of two wavelengths can be completed simultaneously without extra measurement devices. The numerical and experimental results show the feasibility and high precision of the self-calibration method, which enables the rainbow refractometry to be implemented in a more powerful and convenient way. The self-calibrated rainbow system is successfully applied to measure the refractive indices of ethanol-water solutions with volume concentrations of 10% to 60%.
Chinese Optics Letters
- Publication Date: Apr. 10, 2017
- Vol. 15, Issue 4, 042902 (2017)
Simulation of Brillouin gain properties in a double-clad As2Se3 chalcogenide photonic crystal fiber
Xin Chen, Li Xia, Wei Li, and Chen Li
The Brillouin gain properties in a double-clad As2Se3 photonic crystal fiber (PCF) are simulated based on the finite-element method (FEM). The results indicate that the Brillouin gain spectrum (BGS) of our proposed chalcogenide PCF exhibits a multipeaked behavior and has a high Brillouin gain coefficient. We also find that a larger size of inner cladding air holes will lead to a more pronounced second peak in the BGS. On the other hand, the size of the outer cladding has nearly no effect on the BGS behavior. Through these results, one can tailor the Stimulated Brillouin scattering effect in PCFs for a wide range of applications. The Brillouin gain properties in a double-clad As2Se3 photonic crystal fiber (PCF) are simulated based on the finite-element method (FEM). The results indicate that the Brillouin gain spectrum (BGS) of our proposed chalcogenide PCF exhibits a multipeaked behavior and has a high Brillouin gain coefficient. We also find that a larger size of inner cladding air holes will lead to a more pronounced second peak in the BGS. On the other hand, the size of the outer cladding has nearly no effect on the BGS behavior. Through these results, one can tailor the Stimulated Brillouin scattering effect in PCFs for a wide range of applications.
Chinese Optics Letters
- Publication Date: Apr. 10, 2017
- Vol. 15, Issue 4, 042901 (2017)
Static light scattering properties of a ZnO nanosphere aqueous suspension at visible and near-infrared wavelengths
Haopeng Wu, Jiulin Shi, Feng Yan, Junjie Yang, Yubao Zhang, and Xingdao He
The scattering properties of ZnO nanospheres with four different particle diameters of 10, 50, 100, and 200 nm suspended in water are investigated theoretical and experimentally in the spectral range of the entire visible range and part of the near-infrared region. The scattering properties of ZnO nanospheres suspended in water are described by employing three main parameters: the angular distribution of the scattering intensity I, the scattering extinction coefficient αscat, and the scattering cross section σscat. The results indicate that (i) at a certain wavelength, the angular distribution of the scattering intensity appears as an obviously forward-propagating feature, and the forward-scattering intensity is dominant gradually when the particle diameter increases from 10 to 200 nm, and (ii) the scattering extinction coefficient and cross section can be determined by using the measured transmittance changes of a pure water sample and a given ZnO sample; they all are shown to be dependent on the particle size and incident wavelength. The experimental results of four different scattering samples agree well with the theoretical predictions within the given wavelength range. The scattering properties of ZnO nanospheres with four different particle diameters of 10, 50, 100, and 200 nm suspended in water are investigated theoretical and experimentally in the spectral range of the entire visible range and part of the near-infrared region. The scattering properties of ZnO nanospheres suspended in water are described by employing three main parameters: the angular distribution of the scattering intensity I, the scattering extinction coefficient αscat, and the scattering cross section σscat. The results indicate that (i) at a certain wavelength, the angular distribution of the scattering intensity appears as an obviously forward-propagating feature, and the forward-scattering intensity is dominant gradually when the particle diameter increases from 10 to 200 nm, and (ii) the scattering extinction coefficient and cross section can be determined by using the measured transmittance changes of a pure water sample and a given ZnO sample; they all are shown to be dependent on the particle size and incident wavelength. The experimental results of four different scattering samples agree well with the theoretical predictions within the given wavelength range.
Chinese Optics Letters
- Publication Date: Jan. 10, 2017
- Vol. 15, Issue 1, 012901 (2017)
Research on the fractal model and calibration of the aerosol mass concentration measurement based on the particle group light scattering
Fang Gu, Yi Liu, Jiahong Zhang, Yunyun Chen, and Fengping Cui
In order to improve the inversion precision of aerosol mass concentrations based on the particle group light scattering method, the concept that particles through a laser beam are equivalent to an aggregate is proposed. A fractal model for aerosol mass concentration using the signal amplitude distribution of aggregates is presented, and then the subsection calibration method is given. The experimental results show that the mass concentrations inversed by this model agree well with those measured by the norm-referenced instrument. The average relative errors of the two experiments are 5.6% and 6.0%, respectively, which are less than those obtained by the conventional inversion model. In order to improve the inversion precision of aerosol mass concentrations based on the particle group light scattering method, the concept that particles through a laser beam are equivalent to an aggregate is proposed. A fractal model for aerosol mass concentration using the signal amplitude distribution of aggregates is presented, and then the subsection calibration method is given. The experimental results show that the mass concentrations inversed by this model agree well with those measured by the norm-referenced instrument. The average relative errors of the two experiments are 5.6% and 6.0%, respectively, which are less than those obtained by the conventional inversion model.
Chinese Optics Letters
- Publication Date: Nov. 10, 2016
- Vol. 14, Issue 11, 112901 (2016)
Detection of colorless plastic contaminants hidden in cotton layer using chromatic polarization imaging
Bo Peng, Shaling Huang, and Dongjie Li
A method of chromatic polarization imaging is presented for the online detection of colorless plastic contaminants from ginned cotton in an industrial setting. To understand the experimental results, we consider a realistic microscopic model, including the multiple scattering of anisotropic fibers and the light propagation in anisotropic slabs. A Monte Carlo code, based on the extended Jones matrix, is developed to simulate photon migration with polarization states, and phase information followed. Using simulations and experiments, we analyze the underlying mechanisms and evaluate the performance of this method with different layer thicknesses. Our approaches proposed in this Letter also have the potential to be applied in tissue imaging, remote sensing, and other scenarios. A method of chromatic polarization imaging is presented for the online detection of colorless plastic contaminants from ginned cotton in an industrial setting. To understand the experimental results, we consider a realistic microscopic model, including the multiple scattering of anisotropic fibers and the light propagation in anisotropic slabs. A Monte Carlo code, based on the extended Jones matrix, is developed to simulate photon migration with polarization states, and phase information followed. Using simulations and experiments, we analyze the underlying mechanisms and evaluate the performance of this method with different layer thicknesses. Our approaches proposed in this Letter also have the potential to be applied in tissue imaging, remote sensing, and other scenarios.
Chinese Optics Letters
- Publication Date: Sep. 10, 2015
- Vol. 13, Issue 9, 092901 (2015)
The influence of the characteristics of a collection of particles on the scattered spectral density and its applications
Tao Wang, Yi Ding, Xiaoling Ji, and Daomu Zhao
The far-zone scattered spectral density of a light wave on the scattering from a collection of particles is investigated, and the relationship between the character of the collection and the distribution of the scattered spectral density is discussed. It is shown that both the number of particles and their locations in the collection play roles in the distribution of the far-zone scattered spectral density. This phenomenon may provide a potential method to reconstruct the structure character of a collection of particles from measurements of the far-zone scattered spectral density. The far-zone scattered spectral density of a light wave on the scattering from a collection of particles is investigated, and the relationship between the character of the collection and the distribution of the scattered spectral density is discussed. It is shown that both the number of particles and their locations in the collection play roles in the distribution of the far-zone scattered spectral density. This phenomenon may provide a potential method to reconstruct the structure character of a collection of particles from measurements of the far-zone scattered spectral density.
Chinese Optics Letters
- Publication Date: Oct. 10, 2015
- Vol. 13, Issue 10, 102901 (2015)
Using fence pulses to suppress stimulated Raman scattering effect in laser–plasma interaction
Yuliang Zhou, Zhan Sui, Yuanchao Geng, Lixin Xu, and Hai Ming
In inertial confinement fusion, the laser–plasma interaction (LPI) happens when the high-energy laser irradi-ates on the target where the scattered light share generated from the stimulated Raman scattering (SRS) effect is difficult to suppress. We propose a method using fence pulses (FPs) to suppress the backward SRS by inhibiting the growth of the intensity of electron plasma waves. Based on our simulation, the FPs can weaken SRS effect in the LPI effectively. In inertial confinement fusion, the laser–plasma interaction (LPI) happens when the high-energy laser irradi-ates on the target where the scattered light share generated from the stimulated Raman scattering (SRS) effect is difficult to suppress. We propose a method using fence pulses (FPs) to suppress the backward SRS by inhibiting the growth of the intensity of electron plasma waves. Based on our simulation, the FPs can weaken SRS effect in the LPI effectively.
Chinese Optics Letters
- Publication Date: Aug. 22, 2014
- Vol. 12, Issue 9, 092902 (2014)
Calculation and analysis of Mueller matrix in light scattering detection
Keding Yan, Shouyu Wang, Shu Jiang, Liang Xue, Yuanyuan Song, Zhengang Yan, and Zhenhua Li
A new criterion for target detection and identification is proposed to realize metal/dielectric identification and recognition based on Mueller matrix analysis. By using randomly rough surfaces as targets, numerical calculations are used to prove the robustness and accuracy of the criterion. Moreover, to the best of our knowledge, this is the first time to successfully explain the criterion by theoretical analysis. We believe the work provides an important reference for polarization imaging in laser radar and remote sensing, and so on. A new criterion for target detection and identification is proposed to realize metal/dielectric identification and recognition based on Mueller matrix analysis. By using randomly rough surfaces as targets, numerical calculations are used to prove the robustness and accuracy of the criterion. Moreover, to the best of our knowledge, this is the first time to successfully explain the criterion by theoretical analysis. We believe the work provides an important reference for polarization imaging in laser radar and remote sensing, and so on.
Chinese Optics Letters
- Publication Date: Aug. 22, 2014
- Vol. 12, Issue 9, 092901 (2014)
Design of CASSEGRAIN telescope baffles with honeycomb entrance
Xiaodong Hu, Weike Wang, Qiang Hu, Xing Lei, Qing Wei, Yuanzheng Liu, and Jiliang Wang
The stray radiation suppression in Cassegrain family optical system is presented. The design method for ultra-short outer baffle with honeycomb structure is proposed. Meanwhile the constraint formulas for designing the geometries of primary baffle and secondary baffle are deduced when basing the characteristic and taking vignette into account. According to the ray trace simulated data, the point source transmittance values of the baffle are less than 10-10 when incident angles are larger than the rejection angle. The honeycomb-look front baffle guarantees a comparable performance of stray light suppression with traditional tube baffle, while reducing the size greatly. The stray radiation suppression in Cassegrain family optical system is presented. The design method for ultra-short outer baffle with honeycomb structure is proposed. Meanwhile the constraint formulas for designing the geometries of primary baffle and secondary baffle are deduced when basing the characteristic and taking vignette into account. According to the ray trace simulated data, the point source transmittance values of the baffle are less than 10-10 when incident angles are larger than the rejection angle. The honeycomb-look front baffle guarantees a comparable performance of stray light suppression with traditional tube baffle, while reducing the size greatly.
Chinese Optics Letters
- Publication Date: Jun. 20, 2014
- Vol. 12, Issue 7, 072901 (2014)
Factors affecting the spectrum of an electromagnetic light wave on scattering from a semisoft boundary medium
Tao Wang, Xiaoqing Li, and Xiaoling Ji
The spectrum of an electromagnetic light wave on scattering from a semisoft boundary medium is discussed within the accuracy of the first-order Born approximation. It is shown that spectral shifts and spectral switches are affected both by the polarization of the incident light wave and by the characters of the scattering medium. Moreover, numerical results show that the direction at which the spectral switch occurs is governed by the characters of the scattering medium, whereas the magnitude of the spectral switch is affected by the polarization of the incident light wave. The spectrum of an electromagnetic light wave on scattering from a semisoft boundary medium is discussed within the accuracy of the first-order Born approximation. It is shown that spectral shifts and spectral switches are affected both by the polarization of the incident light wave and by the characters of the scattering medium. Moreover, numerical results show that the direction at which the spectral switch occurs is governed by the characters of the scattering medium, whereas the magnitude of the spectral switch is affected by the polarization of the incident light wave.
Chinese Optics Letters
- Publication Date: Nov. 14, 2014
- Vol. 12, Issue 12, 122901 (2014)
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