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Human Brain Imaging by Optical Coherence Tomography
Published in Francesco S. Pavone, Shy Shoham, Handbook of Neurophotonics, 2020
Caroline Magnain, Jean C. Augustinack, David Boas, Bruce Fischl, Taner Akkin, Ender Konukoglu, Hui Wang
The Mueller calculus along with the Stokes parameter provide a more comprehensive description of light polarization in turbid media, including the effect of depolarization. The Stokes parameter S is a vector [I,Q,U,V] where I is the total intensity, and Q, U, and V represent the horizontal/vertical component, the ±45° linear component, and the left/right circular component, respectively. The Mueller matrix M is a 4 × 4 matrix which relates the Stokes vector of transmitted light S′ with that of the illuminating light S by S′ = MS (Huard, 1997). PS OCT systems capable of yielding a Mueller matrix have been presented in Yao and Wang (1999) and Yasuno et al. (2002). An approach to realize depth resolved Stokes parameters was presented in de Boer et al. (1999). The effects of multiple scattering and speckle noise on the polarization measurement have been evaluated using a Stokes parameter-based PS OCT, both resulting in a reduction in the degree of polarization (de Boer and Milner, 2002).
Polarimetry
Published in Russell A. Chipman, Wai-Sze Tiffany Lam, Garam Young, Polarized Light and Optical Systems, 2018
Russell A. Chipman, Wai-Sze Tiffany Lam, Garam Young
A Stokes parameters measurement is a set of measurements acquired with a set of polarization analyzers placed into the beam of light. Let the total number of analyzers be Q, with each analyzer Aq specified by index q = 0, 1,..., Q − 1. Assume the incident Stokes parameters are the same for all measurements. The qth measurement generates an output, a flux measurement Pq = Aq·S. A polarimetric measurement matrixW is defined as a Q × 4 matrix with the qth row containing the analyzer vector Aq,
Polarization Measurement
Published in John G. Webster, Halit Eren, Measurement, Instrumentation, and Sensors Handbook, 2017
Both elements of a Jones vector are complex numbers. Jones algebra is convenient for describing perfectly polarized light. Since a light sensor measures only intensity but not electric field in most cases, the Stokes vector is more convenient to use in metrology. The Stokes parameters are four intensity-based parameters used to describe the polarization state of light, represented by S0, S1, S2, S3 or by I, Q, U, V [1–6,14]. The Stokes vector is the set of these Stokes parameters, defined as [4,14]
Optimized dynamic interference smoothing via asynchronous phasemodulation of SSD
Published in Journal of Modern Optics, 2021
Hao Xiong, Zheqiang Zhong, Yinrui Zhang, Bin Zhang
As shown in Equation (10), all the terms in Ix′ are positive whereas some of them in Iy′ are negative. Consequently, the difference between Ix′ and Iy′ appears, which gives rise to the variation of the polarization direction. The Stokes parameters are used to describe the polarization state quantitatively, that is, where Ex′ and Ey′ refer to the field in the x′ and y′ directions, respectively. δ is the phase difference between Ex′ and Ey′.