Utilizing the Young’s double slits and Mach-Zehnder interferometer, we proposed an experimental method to measure the generalized Stokes parameters of a radially polarized random electromagnetic beam. After the parti...Utilizing the Young’s double slits and Mach-Zehnder interferometer, we proposed an experimental method to measure the generalized Stokes parameters of a radially polarized random electromagnetic beam. After the partially coherent beam propagating through the Young’s double slits, the interference fringe is obtained by the help of a Mach-Zehnder interferometer consisting of apertures, quarter-wave plates and polarizers. The electric cross-spectral density matrix is detected by the coherence degree of interference fringe and the density of each single slit. The generalized Stokes parameters can be obtained from the electric cross-spectral density matrix. This experiment measures the generalized Stokes parameters of the random electromagnetic beam successfully. The results show that the spectral degree of coherence for copolarized cases (xx and yy) is similar with that for cross-polaried cases (xy and yx) for the radially polarized random electromagnetic beam. This method will help us determine the change of the polarization and coherence of the light in propagation by detecting the change of the generalized Stokes parameters.展开更多
The statistical properties of the normalized Stokes parameters in a Gaussian stochastic plane wave field are described in detail. Via the expression of the three normalized Stokes parameters, the mean, variance, and h...The statistical properties of the normalized Stokes parameters in a Gaussian stochastic plane wave field are described in detail. Via the expression of the three normalized Stokes parameters, the mean, variance, and high-order moments are calculated, which simplify C. Brosseau＇s results. The new dispersion, normalized contrast function, skewness, and kurtosis are defined to describe the non-Gaussian distribution characteristics, which can be applied to Gaussian wave fields relating to depolarization of light by a spatially random medium.展开更多
Polarization coding is a specific encoding method by using the polarization state of optical signal carrying coded in- formation. It focuses on nonlinear effects, polarization mode dispersion and other issues in high-...Polarization coding is a specific encoding method by using the polarization state of optical signal carrying coded in- formation. It focuses on nonlinear effects, polarization mode dispersion and other issues in high-speed fiber-optic communi- cations. This paper presents a measurement method for polarization state based on elastic-optic modulator. This method not only retains the original advantages of elastic-optic modulator for polarization measurement, but also overcomes the defects of existing methods including high modulation frequency and invalid collection by using array detector. Matlab simulation and experimental verification scheme are given. The feasibility of this method is verified through theoretical analysis, and simulation and experimental results are carried out. The error analysis of the measurement results shows that the method can meet the measurement requirements and provide conditions for using the polarization encoding in high-speed communication.展开更多
In this paper, we present a simple Stokes parameter measurement method for a rotating quarter-wave plate polarimeter. This method is used to construct a model to describe the principle of how the magnitudes of errors ...In this paper, we present a simple Stokes parameter measurement method for a rotating quarter-wave plate polarimeter. This method is used to construct a model to describe the principle of how the magnitudes of errors influence the deviation of the output light Stokes parameter, on the basis of accuracy analysis of the retardance error of the quarter-wave plate, the misalignment of the analyzing polarizer, and the phase shift of the measured signals, which will help us to determine the magnitudes of these errors and then to acquire the correct results of Stokes parameters. The method is validated by the experiments on left-handed circularly polarized and linear horizontal polarization beams. With the improved method, the maximum measurement deviations of Stokes parameters for these two different polarized states are reduced from 2.72% to 2.68%, and from 3.83% to 1.06% respectively. Our results demonstrate that the proposed method can be used as a promising approach to Stokes parameter measurement for a rotating quarter-wave plate polarimeter.展开更多
In this paper, a division-of-amplitude photopolarimeter （DOAP） for measuring the polarization state of a free-electron laser （FEL） pulse is described. The incident FEL beam is divided into four separate beams, and...In this paper, a division-of-amplitude photopolarimeter （DOAP） for measuring the polarization state of a free-electron laser （FEL） pulse is described. The incident FEL beam is divided into four separate beams, and four Stokes parameters can be measured in a single-shot. In the crossed-planar undulators experiment at the Shanghai deep ultraviolet FEL test facility, this DOAP instrument constructed in house responsed accurately and timely while the polarization-state of fully coherent FEL pulses were switched, which is helpful for confirming the crossed-planar undulators technique for short-wavelength FELs.展开更多
文摘Utilizing the Young’s double slits and Mach-Zehnder interferometer, we proposed an experimental method to measure the generalized Stokes parameters of a radially polarized random electromagnetic beam. After the partially coherent beam propagating through the Young’s double slits, the interference fringe is obtained by the help of a Mach-Zehnder interferometer consisting of apertures, quarter-wave plates and polarizers. The electric cross-spectral density matrix is detected by the coherence degree of interference fringe and the density of each single slit. The generalized Stokes parameters can be obtained from the electric cross-spectral density matrix. This experiment measures the generalized Stokes parameters of the random electromagnetic beam successfully. The results show that the spectral degree of coherence for copolarized cases (xx and yy) is similar with that for cross-polaried cases (xy and yx) for the radially polarized random electromagnetic beam. This method will help us determine the change of the polarization and coherence of the light in propagation by detecting the change of the generalized Stokes parameters.
基金National Excellent PhD Paper Funds Supporting (Grant No.08100101)the New Century Excellent Talent Plan in China (Grant No.NCET-04-0997)
文摘The statistical properties of the normalized Stokes parameters in a Gaussian stochastic plane wave field are described in detail. Via the expression of the three normalized Stokes parameters, the mean, variance, and high-order moments are calculated, which simplify C. Brosseau＇s results. The new dispersion, normalized contrast function, skewness, and kurtosis are defined to describe the non-Gaussian distribution characteristics, which can be applied to Gaussian wave fields relating to depolarization of light by a spatially random medium.
基金National Natural Science Foundation for Special of China(61127015)International Science and Technology Cooperative Project(2013DFR10150)Science and Technology Research Fund for Youth of Shanxi(2014021012)
文摘Polarization coding is a specific encoding method by using the polarization state of optical signal carrying coded in- formation. It focuses on nonlinear effects, polarization mode dispersion and other issues in high-speed fiber-optic communi- cations. This paper presents a measurement method for polarization state based on elastic-optic modulator. This method not only retains the original advantages of elastic-optic modulator for polarization measurement, but also overcomes the defects of existing methods including high modulation frequency and invalid collection by using array detector. Matlab simulation and experimental verification scheme are given. The feasibility of this method is verified through theoretical analysis, and simulation and experimental results are carried out. The error analysis of the measurement results shows that the method can meet the measurement requirements and provide conditions for using the polarization encoding in high-speed communication.
基金Project supported by the National High Technology Research and Development Program of China(Grant No.2015AA123702)the National Natural Science Foundation of China(Grant No.61505222)
文摘In this paper, we present a simple Stokes parameter measurement method for a rotating quarter-wave plate polarimeter. This method is used to construct a model to describe the principle of how the magnitudes of errors influence the deviation of the output light Stokes parameter, on the basis of accuracy analysis of the retardance error of the quarter-wave plate, the misalignment of the analyzing polarizer, and the phase shift of the measured signals, which will help us to determine the magnitudes of these errors and then to acquire the correct results of Stokes parameters. The method is validated by the experiments on left-handed circularly polarized and linear horizontal polarization beams. With the improved method, the maximum measurement deviations of Stokes parameters for these two different polarized states are reduced from 2.72% to 2.68%, and from 3.83% to 1.06% respectively. Our results demonstrate that the proposed method can be used as a promising approach to Stokes parameter measurement for a rotating quarter-wave plate polarimeter.
基金Supported by Major State Basic Research Development Program of China(2011CB808300)National Natural Science Foundation of China(11175240,11205234,11322550)
文摘In this paper, a division-of-amplitude photopolarimeter （DOAP） for measuring the polarization state of a free-electron laser （FEL） pulse is described. The incident FEL beam is divided into four separate beams, and four Stokes parameters can be measured in a single-shot. In the crossed-planar undulators experiment at the Shanghai deep ultraviolet FEL test facility, this DOAP instrument constructed in house responsed accurately and timely while the polarization-state of fully coherent FEL pulses were switched, which is helpful for confirming the crossed-planar undulators technique for short-wavelength FELs.
