Novel nulling spectropolarimeter design for polarization measurement of the cosmic microwave background

After the current Phase 3 of Cosmic Microwave Background (CMB) polarization measurements, aimed at the detection of the B-mode, there is a need of new experiments with higher sensitivity, better control of systematic effects, and the capability to separate polarized contaminants. Using the transfer matrix function method, we designed a novel experimental configuration, working as a nulling spectropolarimeter. This optical design has the capability to retrieve the spectral information of the sole linear polarization component of the incident radiation, rejecting unpolarized radiation. We present the optical design, its main features and an end-to-end forecast simulation about the absolute polarization angle measurement. This measurement is crucial for forthcoming experiments which aim to measure CMB B-mode.