ADDRESSING SPECTRAL ARTIFACTS FROM A ROTATING-BIPLATE-RETARDER STOKES SPECTROPOLARIMETER

Ruan L. S. Lima (DR); UFPA; Paulo T. Araújo; UA; NEWTON MARTINS BARBOSA NETO

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Paper Title

ADDRESSING SPECTRAL ARTIFACTS FROM A ROTATING-BIPLATE-RETARDER STOKES SPECTROPOLARIMETER

Authors

Ruan L. S. Lima (DR); UFPA
Paulo T. Araújo; UA
NEWTON MARTINS BARBOSA NETO

Modality

Pôster

Subject area

Síntese e caracterização de materiais

Publishing Date

12/12/2023

Country of Publishing

Brasil

Language of Publishing

Inglês

Paper Page

https://www.even3.com.br/anais/workshop-do-ineo-2023/611602-addressing-spectral-artifacts-from-a-rotating-biplate-retarder-stokes-spectropolarimeter

ISBN

978-65-272-0088-8

Keywords

Polarization, Stokes Parameters, Artifacts, Waveplate, Spectropolarimetry

Summary

Polarimetry is the technique capable of fully determining the polarization state of a light beam; i.e., the fraction of detected light that is polarized, and how that portion’s ellipse of polarization is characterized. Among many versions, the rotating quarter-wave plate polarimeter is a cheap and versatile option which has been implemented in several single-wavelength applications to determine the Stokes parameters of light through the Stokes-Mueller formalism and the Fourier analysis of the transmitted signal. This technique consists in acquiring transmitted intensities of light through a rotating retarder at finite steps of its fast axis angular position, and a fixed linear polarizer (analyzer). The detected signal is harmonically modulated over such rotation, and the amplitudes of specific modes, determined by Fourier analysis, are linearly dependent of the Stokes parameters of the incoming light. The extension of such technique to spectroscopic measurements is of great interest to the materials research community, since the vectorial nature of light’s polarization is quite sensitive to anisotropic interactions. However, even though achievable, spectral measurements demand for achromatic polarizing elements, such that their modeling for data processing requires special attention, especially the quarter-wave plate. In this work, we implemented a rotating-retarder polarimeter for spectral measurements with a quasi-achromatic biplate retarder over the visible range (400-800 nm), a Glan-Taylor calcite polarizer as analyzer, and a portable USB spectrometer. In this work, we probed strong and recurring signs of artifacts in the spectral measurements of Stokes parameters by initially assuming an ideal achromatic behavior in the mathematical modeling of the rotating retarder. The acquired spectra of derived parameters, such as the polarization degree, the ellipse of polarization’s inclination angle and ellipticity, demonstrate enough evidences to conclude that the idealistic assumption yields an inadequate model of the system. By analyzing the spectral artifacts stemmed from that calibration set, and after a review of the literature, a better model for a quasi-achromatic biplate retarder was developed under Jones’ optical equivalence theorem, such that the real Stokes parameters could be determined apart from the newly arisen intrinsic dispersive properties of the biplate; its equivalent rotatory angle, fast axis tilt, and retardance, or phase-shift. Furthermore, here we present the mathematical and experimental methodology to have them properly characterized and taken as correction terms in the polarimetric data processing of later measurements. Besides, we show an enhancement in precision on new simulated states, as well as on simple applications in solution samples, which corroborates that the remodeling of the retarder for the Fourier analysis is necessary, and therefore, the approach developed here is essential for reliable and trustworthy spectropolarimetric data generation and analysis.

Title of the Event: Workshop do INEO 2023
City of the Event: Nazaré Paulista
Title of the Proceedings of the event: Anais do Workshop INEO 2023
Name of the Publisher: Even3
Means of Dissemination: Meio Digital

How to cite

UFPA, Ruan L. S. Lima (DR);; UA, Paulo T. Araújo;; NETO, NEWTON MARTINS BARBOSA. ADDRESSING SPECTRAL ARTIFACTS FROM A ROTATING-BIPLATE-RETARDER STOKES SPECTROPOLARIMETER.. In: Anais do workshop INEO 2023. Anais...Nazaré Paulista(SP) Hotel Estância Atibainha, 2023. Available in: https//www.even3.com.br/anais/workshop-do-ineo-2023/611602-ADDRESSING-SPECTRAL-ARTIFACTS-FROM-A-ROTATING-BIPLATE-RETARDER-STOKES-SPECTROPOLARIMETER. Access in: 13/10/2024