Characterization of a Double Wollaston Module for Polarimetry in Astrophysics

Abstract

The Wedge Double Wollaston (WeDoWo) or "double Wollaston" module is a device capable of displaying four images of a single field of view (FOV); each image corresponds to a different polarization angle (0^°, 45^°, 90^°, and 135^°), providing enough information for the Stokes I, Q, and U parameters calculation and the linear polarization angle and fraction values retrieved from the source observed, in this case, an astronomical source, in a single exposure (single-shot). In this paper, we present the design of a SiO₂ (Crystalline Silica) WeDoWo module, describe the characterization process carried out in the laboratory and the subsequent calibration. Likewise, we show the application of this module for imaging astronomical polarimetry using the 1.0-meter telescope of the National Astronomical Observatory from Tonantzintla, Puebla (OAN-TNT), and illustrate the advantages and limitations of this technique and the optimal performance of this module.