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Hier finden Sie wissenschaftliche Publikationen aus den FraunhoferInstituten. Simplified Stokes polarimeter based on divisionofamplitude
 Rosenberger, M. ; Society of PhotoOptical Instrumentation Engineers SPIE, Bellingham/Wash.: Photonics and Education in Measurement Science 2019 : 1719 September 2019, Jena, Germany Bellingham, WA: SPIE, 2019 (Proceedings of SPIE 11144) ISBN: 9781510629813 ISBN: 9781510629820 Paper 111441B, 10 pp. 
 Conference "Photonics and Education in Measurement Science" <2019, Jena> 

 English 
 Conference Paper, Electronic Publication 
 Fraunhofer IOSB () 
 polarimetry; ellipsometry; stokes vector; polarization state detector; divisionofamplitude; beamsplitter; retarder; quarterwave plate 
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 divisionofamplitude 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, cos2 2ψr = 1/3, ψt = π/2  ψr, and ΔrΔt modulo π=π/2 by calculating the maximum of the absolute value of determinant of the instrument matrix. Using additional quarterwave 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 ΔrΔt, 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 quarterwave plate instead of two, if one of the Wollaston prisms is rotated.