Polarimetric calibration of large mirrors

TL;DR

This paper introduces a novel polarimetric calibration method for large astronomical mirrors that leverages mirror symmetry properties and known polarization orientations, eliminating the need for specialized optical devices.

Contribution

It presents a new calibration technique based on Mueller matrix symmetries and known polarization orientations, applicable to single and multiple mirrors without requiring detailed polarization knowledge.

Findings

Method effectively calibrates single mirrors using known polarization targets.

Analyzes uncertainties and signal-to-noise requirements for calibration accuracy.

Extends calibration approach to systems with multiple mirrors sharing the same incidence plane.

Abstract

Aims: To propose a method for the polarimetric calibration of large astronomical mirrors that does not require use of special optical devices nor knowledge of the exact polarization properties of the calibration target. Methods: We study the symmetries of the Mueller matrix of mirrors to exploit them for polarimetric calibration under the assumptions that only the orientation of the linear polarization plane of the calibration target is known with certainty. Results: A method is proposed to calibrate the polarization effects of single astronomical mirrors by the observation of calibration targets with known orientation of the linear polarization. We study the uncertainties of the method and the signal-to-noise ratios required for an acceptable calibration. We list astronomical targets ready for the method. We finally extend the method to the calibration of two or more mirrors, in particular to the case when they share the same incidence plane.