Papers by Keyword: Stokes Vector

Abstract: The device errors of a rotating-wave-plate-based polarization measurement system can be mainly categorized as the angle error of the polarization prism, the fast axis angle error of wave-plate and the retardation error. By applying Fourier analysis to solve Stokes vectors, we obtain the formulas to calculate the three errors mentioned above, using linear 0° and 45° polarized light to illuminate the system for the error solving. We analyze the measurement errors of the degree of polarization, the polarization purity and the intensity of polarization state, under certain simulation conditions. The results show that after the calibration, the measurement accuracy is improved. Finally, we analyze the effects of the angle error of the linear polarized light used for calibration to the measurement of the three parameters.

Abstract: Comparing to ordinary light intensity measurements, polarization measurements have many advantages in studying the surface，atmosphere and exploring space. In order to obtain high-quality polarization information, the paper designs a three-channel synchronous acquisition device. It researches the feasibility of obtaining the characteristics information of material surface by polarization vision. It respectively measures the leaves, automobiles, cement wall these three samples’ reflected light’s polarization characteristics using the method of getting Stokes parameters. The experimental results show that the polarization characteristics have a great relationship with the characteristics of target, the measurement wavelength and the viewing angle. The method mentioned in this paper is vital to achieving material surface characteristics. At the same time , it provides a new way for geology and mineral resources exploration.

Abstract: An in-line all-fiber measurement system for polarization parameters is designed and fabricated in this paper. This system implements accurate control of polarization state, together with in-line, accurate, and high-speed measurement of Stokes vector. It can measure the light polarization parameters such as States of Polarization (SOP), Degree of Polarization (DOP), Light Polarization Extinction Ratio (LPER), and related losses of polarization. Besides, polarization monitoring and stabilizing can be achieved using this system. Because there is no discrete device concluded, the optical path of this system is completely constituted by optical fiber, which makes the entire system low-cost, with small size and low insertion loss. Keywords: All-fiber, polarization control, polarization measurement, in-line system, Stokes vector

Abstract: A new system has been developed and calibrated to measure the characteristics and distribution of skylight polarization. With a series of measurements obtained, we verified that the distribution of degree and angle of skylight polarization accords well with the predictions of Rayleigh scattering. The differences of the characteristics and distribution of skylight polarization across the principal plane owning to measurements’ errors have been analyzed and discussed.

Abstract: This paper demonstrates instantaneous phase-stepping and subsequent phase analysis methods for interferometry and two-dimensional photoelasticity. The camera that has a pixelated form-birefringent micro-retarder array acquires phase-stepped fringes in a single camera frame. Then, the distributions of Stokes parameters that represent the state of polarization are calculated from a single image. In the case of the polarization interferometer, the phase difference of the two orthogonally polarized light beam can be easily determined from the Stokes parameters. On the other hand, the phase distributions of the isochromatics and the isoclinics are obtained in the case of the photoelasticity. It is emphasized that this method is applicable to real-time inspection of optical elements as well as the study of the mechanics of time-dependent materials because multiple exposures are unnecessary for sufficient data acquisition in the completion of data analysis.