Pupil Plane Multiplexing for Vectorial Fourier Ptychography

ABSTRACT We present a flexible and cost‐effective computational imaging framework for multichannel microscopy based on pupil plane multiplexing, enabling efficient spectral and polarization‐resolved imaging without bulky optical components. Conventional multichannel systems require sequential acquisition or hardware‐level multiplexing, often requiring complex optics or costly sensor modifications. Our method introduces a custom‐designed pupil division aperture at the microscope's Fourier plane, segmenting the pupil with distinct spectral or polarization filters to produce channel‐specific transfer functions. These encoded measurements are decomposed using a model‐based reconstruction algorithm that incorporates the channel‐dependent pupil functions as priors. We validate our approach through simulations across diverse pupil division geometries and experimentally demonstrate pupil plane polarization multiplexing using semicircular‐shaped linear polarizers and a single monochrome sensor. Integrated with Fourier ptychography, our method enables high‐resolution vectorial imaging of birefringent specimens, reconstructing both amplitude and quantitative phase images of two polarization channels, yielding a full Jones matrix without mechanical scanning or specialized sensors. This pupil plane multiplexing scheme offers a compact, modality‐adaptive, and scalable platform for advanced multichannel microscopy.