Calibration methods for division-of-focal-plane polarimeters

Abstract

Division-of-focal plane (DoFP) imaging polarimeters are useful instruments for measuring polarization information for a variety of applications. Recent advances in nanofabrication have enabled the practical manufacture of DoFP sensors for the visible spectrum. These sensors are made by integrating nanowire polarization filters directly with an imaging array, and size variations of the nanowires due to fabrication can cause the optical properties of the filters to vary up to 20% across the imaging array. If left unchecked, these variations introduce significant errors when reconstructing the polarization image. Calibration methods offer a means to correct these errors. This work evaluates a scalar and matrix calibration derived from a mathematical model of the polarimeter behavior. The methods are evaluated quantitatively with an existing DoFP polarimeter under varying illumination intensity and angle of linear polarization.