Deriving Telescope Mueller Matrices Using Daytime Sky Polarization Observations

TL;DR

This paper presents a method to accurately derive the Mueller matrix of a telescope using daytime sky polarization observations, enabling correction of polarization cross-talk without hardware modifications.

Contribution

The paper introduces an efficient, hardware-free technique to recover the telescope's Mueller matrix from daytime sky polarization data.

Findings

Achieved Mueller matrix recovery with a few percent accuracy.

Demonstrated the method on Haleakala 3.7m AEOS telescope.

Validated the technique using highly polarized daytime sky observations.

Abstract

Telescopes often modify the input polarization of a source so that the measured circular or linear output state of the optical signal can be signficantly different from the input. This mixing, or polarization "cross-talk", is defined by the optical system Mueller matrix. We describe here an efficient method for recovering the input polarization state of the light and the full 4 x 4 Mueller matrix of the telescope with an accuracy of a few percent without external masks or telescope hardware modification. Observations of the bright, highly polarized daytime sky using the Haleakala 3.7m AEOS telescope and a coude spectropolarimeter demonstrate the technique.