Deterministic spatial polarization preservation for Mueller matrix microscopy

High numerical aperture objective focusing is essential for resolving subwavelength structures. However, it induces significant transverse polarization crosstalk in Mueller matrix microscopy (MMM). To address this issue, we present an analytical framework to achieve deterministic spatial polarization preservation. By inverting the vectorial diffraction tensor, we prescribe an incident complex amplitude that annihilates orthogonal crosstalk via destructive interference. This active pupil modulation ensures that arbitrary input polarization states are uniformly maintained across the focal plane. Additionally, we develop a complementary algorithm to rectify the secondary distortion arising from the collection objective, which forcibly projects the intrinsic longitudinal field and generates a coherent parasitic background. By cascading both correction strategies, all Mueller matrix elements can be perfectly restored. These findings not only enable distortion-free MMM but also establish a reliable foundation for polarization-sensitive nanofabrication and multidimensional optical storage.