Polarization-Multiplexed Metalens for Far-Field Super-Resolution Imaging

Recent decades have seen an increasing interest in developing super-resolution imaging methods that allow overcoming the diffraction limit. Near-field imaging methods achieve super-resolution by collecting evanescent waves with high spatial frequency components, often having subwavelength working distances or requiring the sample to be placed near a specially structured hyperlens. On the other hand, far-field super-resolution microscopy imaging with fluorescent substances often requires staining the sample. For non-invasive far-field super-resolution imaging systems based on a super-oscillatory lens, the field-of-view is limited by the unwanted sidelobes and sidebands. The throughput efficiency of the super-oscillatory lens dramatically decreases with the reduced size of the main focal spot. Here, we propose a far-field non-invasive super-resolution imaging method based on polarization-multiplexed metalens. By designing and optimizing the polarization-multiplexed, multi-channel point spread functions of the metalens, the system can obtain multi-channel optical information in a single shot. As a result, we obtain a digitally synthesized point spread function with a center hot spot with a small full width at half maximum as well as suppressed sidelobes and sidebands. Such a compact, single-shot super-resolution imaging system could enable new applications in diverse areas ranging from remote sensing to microscopy over a wide field-of-view.