Optimal elliptical retarder in rotating compensator imaging polarimetry

In this Letter, we present a new, to the best of our knowledge, design for elliptical retarders based on two quarter-wave retarders with an angle offset, which is particularly well suited for polarimetric measurements based on rotating compensator systems. We show that this simple elliptical retarder design offers the minimum condition number achieved by traditionally optimal polarimeter setups and can be used to further improve the accuracy of polarimetric imaging measurements in the presence of error sources, with the advantage that it only requires common quarter-wave retarders.