Single-Shot Polarization Imaging of Vectorial Metasurfaces Using Cross-Grating Wavefront Microscopy

Nanophotonics and optical microscopy are now tightly intertwined in modern research, as high-resolution optical characterization is essential for studying nanomaterials, such as dielectric and plasmonic nanoparticles, metasurfaces, and 2D materials. Yet, existing microscopy techniques are often complex to implement or limited to measuring light intensity, overlooking spectral, phase, and polarization features. Here, we report an optical microscopy approach capable of retrieving the full complex vectorial electromagnetic field at the image plane (that is, intensity, phase, and polarization of light) in a single acquisition. The method combines a polarization-sensitive camera with a two-dimensional diffraction grating (cross-grating) placed in close proximity to the image sensor. Beyond light beam characterization, we show how this configuration enables sample characterization in two image acquisitions, through Jones matrix imaging, from which we derive the complex transmittance tensor of metasurfaces. This accessible technique, easy to implement in any preexisting microscope, offers a comprehensive metrology platform for advanced studies of metasurfaces and 2D materials, in line with the growing interest in polarization-resolved nanophotonics.