Mueller-matrix for non-ideal beam-splitters to ease the analysis of vectorial optical fields

Abstract

Non-polarizing beam-splitters (BSs) are the heart of most optical experiments and instruments (optical coherence tomography, holography, optical communication, quantum cryptography, etc.). An ideal BS assumes polarization independence, rare to achieve in a realistic scenario due to BS’ intrinsic nature, which causes errors in polarization-sensitive experiments. This article identifies a solution to this problem by introducing a Mueller matrix (MM) for a realistic BS—which, to the best of our knowledge, is the only way to analyze the effect on vectorial fields. Simulations using the introduced MM assist in understanding modulations in the degree of polarization (DoP) of partially polarized fields after a BS. These changes in DoP by a BS are verified in an experiment by synthesizing a partially polarized beam. Further, the effects of BS on polarization singularities are studied using the matrices both theoretically and experimentally. It is observed that passing partially polarized polarization singular beams through a BS can cause a loss of axial symmetry in polarization features, which is verified through simulations using the introduced MM. This study may find useful applications in most optical experiments and instrumentation.