Journals > > Topics > Physical Optics
Physical Optics|137 Article(s)
Analytical Expression of Gaussian Beam Converted by Axicon-lens System
Mengshi DAI, Chongguang LI, Yuli LOU, and Xiaoxue CHEN
Based on Fraunhofer diffraction integral formula， using convolution theorem and the property of zero-order Hank transform， the analytical mathematical formula of light intensity distribution on the back focal plane of the lens after the fundamental transverse mode Gaussian beam perpendicularly enters the axicon-lens combination optical system is derived， and the mathematical relationship between the bottle beam intensity distribution and the main optical parameters in the axicon-lens combination is established， which provides theoretical support for the rapid simulation of bottle beam intensity distribution and the design of optical system for generating bottle beam. According to the derived formula， the numerical simulation and experiment are carried out， obtaining a uniformly distributed bottle beam with similar ring size， respectively， which verifies the correctness of the theoretical results. Based on Fraunhofer diffraction integral formula， using convolution theorem and the property of zero-order Hank transform， the analytical mathematical formula of light intensity distribution on the back focal plane of the lens after the fundamental transverse mode Gaussian beam perpendicularly enters the axicon-lens combination optical system is derived， and the mathematical relationship between the bottle beam intensity distribution and the main optical parameters in the axicon-lens combination is established， which provides theoretical support for the rapid simulation of bottle beam intensity distribution and the design of optical system for generating bottle beam. According to the derived formula， the numerical simulation and experiment are carried out， obtaining a uniformly distributed bottle beam with similar ring size， respectively， which verifies the correctness of the theoretical results.
Acta Photonica Sinica
- Publication Date: Jul. 25, 2021
- Vol. 50, Issue 7, 298 (2021)
Multiple Magnetic Fano Resonances Based on Single-split Ring and Double-split Disk Structure
Qi-qiang NIU, Yi-ping HUO, Xue-ying JIANG, Chen ZHOU, Yi-yuan GUO, Yi-bo HOU, Qian HE, and Xiang-xiang HAO
The surface plasmon resonances of a nanostructure composed of a single-split ring and a double-split disk is studied theoretically by the finite element method. When the incident light is normal to the structure surface, a magnetic Fano resonance can be generated by the interference between a bright magnetic mode and a dark magnetic mode. High order magnetic modes and double magnetic Fano resonances can be generated when the double-split disk, the cavity, and the gap of the single-split ring offset together along the negative x-axis. On the basis of this structure, further modulating the gap width of the single-split ring, magnetic modes intensity is enhanced in the near-infrared region and triple magnetic Fano resonances is generated; similarly, by modulating the upper split angle of the double-split disk, high-order magnetic mode is obtained in the visible region and triple magnetic Fano resonances is generated. In addition, the maximum sensitivity and magnetic field enhancement of the structure can reach 1 400 nm/RIU and 69.7, respectively. These optical properties make the structure has potential application value in the field of ultra-sensitive biosensor and multi-control magnetic Fano switch. The surface plasmon resonances of a nanostructure composed of a single-split ring and a double-split disk is studied theoretically by the finite element method. When the incident light is normal to the structure surface, a magnetic Fano resonance can be generated by the interference between a bright magnetic mode and a dark magnetic mode. High order magnetic modes and double magnetic Fano resonances can be generated when the double-split disk, the cavity, and the gap of the single-split ring offset together along the negative x-axis. On the basis of this structure, further modulating the gap width of the single-split ring, magnetic modes intensity is enhanced in the near-infrared region and triple magnetic Fano resonances is generated; similarly, by modulating the upper split angle of the double-split disk, high-order magnetic mode is obtained in the visible region and triple magnetic Fano resonances is generated. In addition, the maximum sensitivity and magnetic field enhancement of the structure can reach 1 400 nm/RIU and 69.7, respectively. These optical properties make the structure has potential application value in the field of ultra-sensitive biosensor and multi-control magnetic Fano switch.
Acta Photonica Sinica
- Publication Date: Sep. 25, 2020
- Vol. 49, Issue 9, 0926001 (2020)
Antenna Array Initial Condition Calibration Method for Integrated Optical Phased Array
Qi-hao ZHANG, Ling-xuan ZHANG, Zhong-yu LI, Wei WU, Guo-xi WANG, Xiao-chen SUN, Wei ZHAO, and Wen-fu ZHANG
To solve the problem that the phase error of the optical phased array is difficult to calibrate, rotating element electric field vector calibration method is modified. Comparing with the traditional method, the new method modifies the algorithm and corrects the phase immediately after measuring the phase error of one unit, then measures and corrects the phase of the next unit. Possible π phase error in traditional method is avoided when large initial phase distribution and finite optical power measurement accuracy present. The simulation results show that the main lobe intensity calibrated with the original method reaches at most 70.8% of the ideal value on average, and the standard deviation is at least 19.1%. While after calibration with the modified method the main lobe intensity reaches at least 87.6% of the ideal value on average, the maximum standard deviation is 7.3%. The modified method produces statistically more accurate and predictable calibration result. A 9×9 optical phased array chip is manufactured. The initial grating lobe suppression ratio ofthe chip is 2.12 dB. Calibrated with this modified method the ratio reaches 4.68 dB. The effectiveness and practical application value of this method are proved. To solve the problem that the phase error of the optical phased array is difficult to calibrate, rotating element electric field vector calibration method is modified. Comparing with the traditional method, the new method modifies the algorithm and corrects the phase immediately after measuring the phase error of one unit, then measures and corrects the phase of the next unit. Possible π phase error in traditional method is avoided when large initial phase distribution and finite optical power measurement accuracy present. The simulation results show that the main lobe intensity calibrated with the original method reaches at most 70.8% of the ideal value on average, and the standard deviation is at least 19.1%. While after calibration with the modified method the main lobe intensity reaches at least 87.6% of the ideal value on average, the maximum standard deviation is 7.3%. The modified method produces statistically more accurate and predictable calibration result. A 9×9 optical phased array chip is manufactured. The initial grating lobe suppression ratio ofthe chip is 2.12 dB. Calibrated with this modified method the ratio reaches 4.68 dB. The effectiveness and practical application value of this method are proved.
Acta Photonica Sinica
- Publication Date: Aug. 25, 2020
- Vol. 49, Issue 7, 726001 (2020)
Tightly Focusing Property of Off-axial Vector Beams
Yu LI, Peng LI, Dong-jing WU, and Jian-lin ZHAO
The tightly focusing property of vector beams with off-axial polarization singularities are numerically investigated, according to the Richard-Wolf vector diffraction intergation theory. A method for designing speical focal field is proposed, based on the tightly focusing of vector field with generalized polarization distribution, after analyzing the tightly focusing of radially and azimuthally polarized beams. Moreover, the modulation effect of symmetric broken of off-axial polarization singularites on the focused field, especially the modulation effect on the Spin Angular Momentum (SAM) density, are discussed by analyzing the variation of SAM distributions arising from spin-orbital coupling. The results not only rich the tightly focusing property of vector beam, but also provide reference for improving the distribution of focal field. The tightly focusing property of vector beams with off-axial polarization singularities are numerically investigated, according to the Richard-Wolf vector diffraction intergation theory. A method for designing speical focal field is proposed, based on the tightly focusing of vector field with generalized polarization distribution, after analyzing the tightly focusing of radially and azimuthally polarized beams. Moreover, the modulation effect of symmetric broken of off-axial polarization singularites on the focused field, especially the modulation effect on the Spin Angular Momentum (SAM) density, are discussed by analyzing the variation of SAM distributions arising from spin-orbital coupling. The results not only rich the tightly focusing property of vector beam, but also provide reference for improving the distribution of focal field.
Acta Photonica Sinica
- Publication Date: Apr. 25, 2020
- Vol. 49, Issue 4, 0426002 (2020)
Interaction of Dark Rogue Waves
Ren GAO, Juan-fen WANG, Xuan ZHANG, Ling-zhen YANG, and Zhao-xia ZHANG
The coupled nonlinear Schr?dinger equation was used as a theoretical model to study the interaction of two first-order dark rogue waves in a normal dispersion single-mode fiber. Based on the exact solution of first-order dark rogue wave, the interaction between two adjacent first-order dark rogue waves is discussed in terms of spacing, phase and ratio of amplitude coefficients using split-step Fourier numerical simulation. Based on the exact solution of the second-order dark rogue wave, the nonlinear interaction of two first-order dark rogue waves is discussed.The results show that the interaction of two adjacent in-phase first-order dark rogue waves will generate "twisted" dark rogue waves when the interval parameter T1 is 0, 5, 20. Compared to the energy diffusion of a single dark rogue wave, the "twisted" dark rogue wave can split and form multiple secondary dark rogue waves.In the case of out of-phase, when the interval parameter T1 is 2, 7, 12, the interaction of two adjacent first-order dark rogue waves can also stimulate and generatethe "twisted" dark rogue waves. And the initially excited spatial position of the "twisted" dark rogue wave deviates from that of the original single dark rogue wave.The larger the ratio of amplitude coefficients, the closer this spatial position is to 5.Second-order dark rogue waves can be regarded as the nonlinear superposition of two first-order dark rogue waves.The composite and three-component second-order dark rogue waves are slightly similar to the interaction between two adjacent first-order dark rogue waves. The coupled nonlinear Schr?dinger equation was used as a theoretical model to study the interaction of two first-order dark rogue waves in a normal dispersion single-mode fiber. Based on the exact solution of first-order dark rogue wave, the interaction between two adjacent first-order dark rogue waves is discussed in terms of spacing, phase and ratio of amplitude coefficients using split-step Fourier numerical simulation. Based on the exact solution of the second-order dark rogue wave, the nonlinear interaction of two first-order dark rogue waves is discussed.The results show that the interaction of two adjacent in-phase first-order dark rogue waves will generate "twisted" dark rogue waves when the interval parameter T1 is 0, 5, 20. Compared to the energy diffusion of a single dark rogue wave, the "twisted" dark rogue wave can split and form multiple secondary dark rogue waves.In the case of out of-phase, when the interval parameter T1 is 2, 7, 12, the interaction of two adjacent first-order dark rogue waves can also stimulate and generatethe "twisted" dark rogue waves. And the initially excited spatial position of the "twisted" dark rogue wave deviates from that of the original single dark rogue wave.The larger the ratio of amplitude coefficients, the closer this spatial position is to 5.Second-order dark rogue waves can be regarded as the nonlinear superposition of two first-order dark rogue waves.The composite and three-component second-order dark rogue waves are slightly similar to the interaction between two adjacent first-order dark rogue waves.
Acta Photonica Sinica
- Publication Date: Apr. 25, 2020
- Vol. 49, Issue 4, 0426001 (2020)
Degree of Diffraction for Monochromatic Light Beams
WU Jie, YANG Shuang-yan, and LI Chun-fang
Enlightened by the degree of paraxiality that was recently introduced by Gawhary and Severini in Opt.Lett.33,1360(2008),a parameter,called the degree of diffraction,is defined to describe the diffractive spreading of a monochromatic light beam.This is a parameter that is independent of the degree of paraxiality.Nevertheless,the same as the degree of paraxiality,the degree of diffraction depends only on the angular spectrum of a beam.With this definition,it is ready to compare quantitatively the diffractive spreading of different beams.-WUJie|jiewu@shu.edu.cn Enlightened by the degree of paraxiality that was recently introduced by Gawhary and Severini in Opt.Lett.33,1360(2008),a parameter,called the degree of diffraction,is defined to describe the diffractive spreading of a monochromatic light beam.This is a parameter that is independent of the degree of paraxiality.Nevertheless,the same as the degree of paraxiality,the degree of diffraction depends only on the angular spectrum of a beam.With this definition,it is ready to compare quantitatively the diffractive spreading of different beams.-WUJie|jiewu@shu.edu.cn
Acta Photonica Sinica
- Publication Date: Jan. 01, 2015
- Vol. 44, Issue 1, 126004 (2015)
Focusing Properties of Symmetric Broken Azimuthally Polarized Beams Modulated by Non-uniform Spiral Phases
XIE Gao-feng, LI Peng, LIU Sheng, and ZHAO Jian-lin
The controlling of the distributions of intensity and transversal energy flow in the focal filed of azimuthally polarized beams by multiple parameters was presented. The modulations of non-uniform spiral phase and rotationally symmetric amplitude obstacle on the focusing properties of azimuthally polarized beams were numerically studied,as well as their combined modulation on transversal energy flow and polarization distributions in the focal plane were also analyzed,based on the vectorial diffraction theory. The results demonstrate that the non-uniform spiral phase has significant effects on the focusing properties,and give rise to the shift of gravity of the focused field. With the combined modulation of even-fold rotationally symmetric amplitude obstacle,local elliptical polarization and circular polarization,as well as transversal energy flow appear in the focused field. Additionally,adjusting the phase structure not only can control the gravity of the focused field,but also can further enrich the focal field polarization state and transverse energy flow. This method of controlling the intensity and energy flow of focused field provides a new way to realize the manipulation of particles in special area. The controlling of the distributions of intensity and transversal energy flow in the focal filed of azimuthally polarized beams by multiple parameters was presented. The modulations of non-uniform spiral phase and rotationally symmetric amplitude obstacle on the focusing properties of azimuthally polarized beams were numerically studied,as well as their combined modulation on transversal energy flow and polarization distributions in the focal plane were also analyzed,based on the vectorial diffraction theory. The results demonstrate that the non-uniform spiral phase has significant effects on the focusing properties,and give rise to the shift of gravity of the focused field. With the combined modulation of even-fold rotationally symmetric amplitude obstacle,local elliptical polarization and circular polarization,as well as transversal energy flow appear in the focused field. Additionally,adjusting the phase structure not only can control the gravity of the focused field,but also can further enrich the focal field polarization state and transverse energy flow. This method of controlling the intensity and energy flow of focused field provides a new way to realize the manipulation of particles in special area.
Acta Photonica Sinica
- Publication Date: Jan. 01, 2015
- Vol. 44, Issue 1, 126003 (2015)
Analysis of Waveguide Discontinuities with Anisotropic Dielectric by Semi-analytical Spectral Element Method
YANG Hong-wei, WANG Gai-ye, and HUANG Cui-ying
The spectral element combined with precise integration method was used to simulate and analyze the waveguide discontinuities with anisotropic dielectric.With the variational principle based on single variable corresponding to the vector wave equation,spectral elements,a special type of higher order finite element with sampling points defined as the Gauss-Lobatto-Legendre points,were employed to discretize the cross section of the waveguide structure,which contains anisotropic dielectric.Then the semidiscretized problem was cast into Hamilton system and sloved by the precision integration method.With adopting the spectral elements,high precision of calculation results can be obtained under the low number of unit grids;With the precise integration method,the longitudinal length of structure can be set arbitrarily.It can overcome the weakness of increasing computation amounts as lengthening the distance from artificial boundary to dielectric block.Results show that semi-analytical spectral element method can be used to effectively solve waveguide discontinuities problems,which contains anisotropic dielectric.The proposed methords is demanstrated to solve waveguide discontinuities problems with high computational accuracy and efficiency. The spectral element combined with precise integration method was used to simulate and analyze the waveguide discontinuities with anisotropic dielectric.With the variational principle based on single variable corresponding to the vector wave equation,spectral elements,a special type of higher order finite element with sampling points defined as the Gauss-Lobatto-Legendre points,were employed to discretize the cross section of the waveguide structure,which contains anisotropic dielectric.Then the semidiscretized problem was cast into Hamilton system and sloved by the precision integration method.With adopting the spectral elements,high precision of calculation results can be obtained under the low number of unit grids;With the precise integration method,the longitudinal length of structure can be set arbitrarily.It can overcome the weakness of increasing computation amounts as lengthening the distance from artificial boundary to dielectric block.Results show that semi-analytical spectral element method can be used to effectively solve waveguide discontinuities problems,which contains anisotropic dielectric.The proposed methords is demanstrated to solve waveguide discontinuities problems with high computational accuracy and efficiency.
Acta Photonica Sinica
- Publication Date: Jan. 01, 2015
- Vol. 44, Issue 1, 126002 (2015)
Effects of the Aperture on Polarization Properties of Polarized Gaussian Schell-model Beam
LIU Jun, CAO Xing, GAO Ming, LV Hong, and GONG Lei
According to the extended Huygens-Fresnel principle and Collins formula, based on complex Gaussian function expansion method, the cross-spectral density formula of elliptically polarized Gaussian Schell-model beam passing through the rectangular aperture was derived. Meanwhile combined the Stokes vector theory, the expressions of light intensity, the degree of polarization, the orientation angle and the degree of ellipticity on the receiver plane were studied. Furthermore, the effects of diaphragm aperture obscuration ratio on the light intensity, the degree of polarization, the orientation angle and the degree of ellipticity were analyzed. The results show that the light intensity and polarization properties of polarized Gaussian Schell-model beam passing through the aperture exhibit variation with oscillations, and effects of aperture obscuration ratio on them are drastic, especially in the near-field region. Besides, with the increasing of the transmission distance, effects of the aperture on the light intensity and polarization properties are reduced. According to the extended Huygens-Fresnel principle and Collins formula, based on complex Gaussian function expansion method, the cross-spectral density formula of elliptically polarized Gaussian Schell-model beam passing through the rectangular aperture was derived. Meanwhile combined the Stokes vector theory, the expressions of light intensity, the degree of polarization, the orientation angle and the degree of ellipticity on the receiver plane were studied. Furthermore, the effects of diaphragm aperture obscuration ratio on the light intensity, the degree of polarization, the orientation angle and the degree of ellipticity were analyzed. The results show that the light intensity and polarization properties of polarized Gaussian Schell-model beam passing through the aperture exhibit variation with oscillations, and effects of aperture obscuration ratio on them are drastic, especially in the near-field region. Besides, with the increasing of the transmission distance, effects of the aperture on the light intensity and polarization properties are reduced.
Acta Photonica Sinica
- Publication Date: Jan. 01, 2015
- Vol. 44, Issue 1, 126001 (2015)
Attenuation Characteristics of Laser in the Randomly Distributed Soot Agglomerates
LEI Cheng-xin, WU Zhen-sen, ZHANG Hua-fu, and LIU Han-fa
Based on fractal theory,the cluster-cluster aggregation (CCA) model is used to simulate the fractal structure of the soot agglomerates with random distribution,and the properties of single scattering of randomly distributed soot agglomerates are studied using the discrete dipole approximation (DDA) method.Then the laser attenuation characteristics in the randomly distributed soot cluster agglomerates are studied using Monto Carlo method.The effects of the incident angle,laser wavelength,number concentration,the number and diameter of primary particles in soot agglomerates on the attenuation properties of laser are discussed.The research result provides theoretical basis to the propagation and attenuation characteristics of laser in the complex random medium. Based on fractal theory,the cluster-cluster aggregation (CCA) model is used to simulate the fractal structure of the soot agglomerates with random distribution,and the properties of single scattering of randomly distributed soot agglomerates are studied using the discrete dipole approximation (DDA) method.Then the laser attenuation characteristics in the randomly distributed soot cluster agglomerates are studied using Monto Carlo method.The effects of the incident angle,laser wavelength,number concentration,the number and diameter of primary particles in soot agglomerates on the attenuation properties of laser are discussed.The research result provides theoretical basis to the propagation and attenuation characteristics of laser in the complex random medium.
Acta Photonica Sinica
- Publication Date: Aug. 24, 2021
- Vol. 39, Issue 6, 1021 (2010)
Topics
© Copyright 2018-2021 | Chinese Laser Press. All Rights Reserved 沪ICP备15018463号-20