3D point scanning super-resolution microscopy via polarization modulation.

We report a new approach to achieving super-resolution in point-scanning microscopy through polarization modulation for the first time, to the best of our knowledge. By modulating linearly polarized incident light, the emission extent of fluorescent dyes changes periodically, adding sparsity in each recording, which contributes to the super-resolution reconstruction. To recover the super-resolution result, a sparse penalty-based deconvolution method is implemented onto the polarization-modulated dataset subsequently. By simply inserting a vortex half-wave retarder into a typical confocal microscope, we obtain the super-resolution experimental results of both nuclear pore complex proteins and tubulins in vero cells, which evidence a sub-diffraction resolution of λ/5. In addition, three-dimensional (3D) super-resolution on spatial distributed single molecules is simulated, where the significant resolution improvement in both lateral and axial directions further confirms its capacity in 3D imaging applications. Considering no constraint on fluorescence dyes and easy implementation in a point-scanning microscope, we envision that the polarization-modulated confocal microscope would be a helpful alternative in biological imaging.