Spectral line polarimetry with a channeled polarimeter
| Autor: | Christoph U. Keller, Frans Snik, Jeroen Rietjens, J. Martijn Smit, Gerard van Harten |
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| Rok vydání: | 2014 |
| Předmět: |
Physics
business.industry media_common.quotation_subject Astrophysics::Instrumentation and Methods for Astrophysics Diffuse sky radiation Polarimetry Polarimeter Polarization (waves) Atomic and Molecular Physics and Optics Spectral line Optics Sky Photon polarization Electrical and Electronic Engineering business Engineering (miscellaneous) Circular polarization media_common |
| Zdroj: | Applied Optics. 53:4187 |
| ISSN: | 2155-3165 1559-128X |
| DOI: | 10.1364/ao.53.004187 |
| Popis: | Channeled spectropolarimetry or spectral polarization modulation is an accurate technique for measuring the continuum polarization in one shot with no moving parts. We show how a dual-beam implementation also enables spectral line polarimetry at the intrinsic resolution, as in a classic beam-splitting polarimeter. Recording redundant polarization information in the two spectrally modulated beams of a polarizing beam-splitter even provides the possibility to perform a postfacto differential transmission correction that improves the accuracy of the spectral line polarimetry. We perform an error analysis to compare the accuracy of spectral line polarimetry to continuum polarimetry, degraded by a residual dark signal and differential transmission, as well as to quantify the impact of the transmission correction. We demonstrate the new techniques with a blue sky polarization measurement around the oxygen A absorption band using the groundSPEX instrument, yielding a polarization in the deepest part of the band of 0.160±0.010, significantly different from the polarization in the continuum of 0.2284±0.0004. The presented methods are applicable to any dual-beam channeled polarimeter, including implementations for snapshot imaging polarimetry. |
| Databáze: | OpenAIRE |
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