Full-Dimensional Photonic Spin-Hall Spatial Differential Imaging

Abstract

Photonic spin-Hall effects (PSHEs), originating from the interaction between spin and orbital angular momenta, have been widely investigated for amplitude and phase spatial differential imaging. However, PSHE-based optical spatial differential imaging methods impose strict requirements on the polarization of the input field, limiting their application in scenarios where the polarization state of the light cannot be easily controlled or the input field is inherently a polarization field. Here, we propose an optical differentiator utilizing cascaded PSHEs to achieve full-dimensional optical spatial differential imaging. By creating giant and tiny PSHEs using liquid-crystal half-wave and quarter-wave polarization gratings, the input field is separated into two circular polarization basis vectors for independent differentiation operations. We demonstrate that this differentiator enables differential imaging of amplitude, phase, and polarization fields. Furthermore, we achieve controllable contrast in the differential images of the two circular polarization basis vectors by longitudinally or transversely moving the half-wave or quarter-wave polarization grating. Our findings might open up new possibilities for applications in areas such as advanced imaging techniques, material characterization, and optical information processing.