Plane wave configuration for spectroscopic Mueller matrices and diffraction efficiencies of polarization beam splitting metasurfaces at normal and oblique incidence

Transmission polarization beam splitting metasurfaces (MSs) made of dielectric resonators are investigated using diffractive order Mueller Matrix Ellipsometry (MME) in a plane wave configuration using a collimated beam. We demonstrate that this method accurately captures the spectral dependency of the diffraction efficiencies of small prototype MS samples by adding adjustable precision pinholes. The normalized Mueller matrix elements are in excellent correspondence to previous reports. We demonstrate that diffracted order MME with collimated beam measurements allows both to measure larger diffraction angles (i.e., the spectroscopic response) and the angle of incidence dependency of MS devices. As a result, a more complete response of polarization beam splitting MSs is obtained, with full width half maximum of the efficiency of approximately 180 nm at normal incidence, with only a small degradation of the diffraction efficiency and the polarimetric properties for incidence angles up to 20 °. For the circular beam splitting polarizer MS, we find one mode that appears highly protected against variations in the incidence angles.