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Proceedings Paper • Open Access

Simplified Stokes polarimeter based on division-of-amplitude
Author(s): Christian Negara; Zheng Li; Thomas Längle; Jürgen Beyerer

Paper Abstract

A polarization state detector (PSD) measures the state of polarization of the detected light. The state of polarization is fully described by the Stokes vector containing four Stokes parameters. A division-of-amplitude photopolarimeter (DOAP) measures the four Stokes parameters by simultaneously acquiring four intensities using photodetectors. A key component of the DOAP is the first beam splitter, which splits up the incoming beam into two beams. The effect of the beam splitter on the state of polarization of the reflected (r) and transmitted (t) beam is determined by six parameters: R, T, ψr, ψt, Δr, and Δt. R and T are the reflectance and transmittance, and (ψr, Δr) and (ψt, Δt) are the ellipsometric parameters of the beam splitter in reflection and transmission, respectively. To measure the Stokes vector with high accuracy, the six optical parameters must be chosen appropriately. In previous work, the optimal parameters of the beam splitter have been determined as R = T = 1/2, cos2r = 1/3, ψt = π/2 - ψr, and Δrt modulo π=π/2 by calculating the maximum of the absolute value of determinant of the instrument matrix. Using additional quarter-wave plates eliminates the constraint on the retardance and hence simplifies the manufacturing process of the beam splitter, especially when broadband application is intended. To compensate a suboptimal value of Δrt, the azimuthal angles of the principal axes of the retarders must be adjusted, for which we provide analytic formulas. Hence, a DOAP with retarders is also optimal in the sense that the same values for the determinant and condition number of the instrument matrix are obtained. When using two additional retarders, it is necessary to install both on the same light path in order to obtain an optimal DOAP. We will show that is also possible to get an optimal DOAP with only one additional quarter-wave plate instead of two, if one of the Wollaston prisms is rotated.

Paper Details

Date Published: 17 September 2019
PDF: 10 pages
Proc. SPIE 11144, Photonics and Education in Measurement Science 2019, 111441B (17 September 2019);
Show Author Affiliations
Christian Negara, Fraunhofer Institute of Optronics, System Technologies and Image Exploitation (Germany)
Zheng Li, Fraunhofer Institute of Optronics, System Technologies and Image Exploitation (Germany)
Karlsruhe Institute of Technology (Germany)
Thomas Längle, Fraunhofer Institute of Optronics, System Technologies and Image Exploitation (Germany)
Jürgen Beyerer, Fraunhofer Institute of Optronics, System Technologies and Image Exploitation (Germany)
Karlsruhe Institute of Technology (Germany)


Published in SPIE Proceedings Vol. 11144:
Photonics and Education in Measurement Science 2019
Maik Rosenberger; Paul-Gerald Dittrich; Bernhard Zagar, Editor(s)

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