Phase-contrast super-resolution microscopy based on super-oscillation illumination

• A label-free super-resolution phase-contrast microscopy based on super- oscillation illuminating metalens. • Our method can resolve a phase-type grating with a linewidth of 120 nm, a pitch of 240 nm, and a phase difference of 0.5π. • Phase contrast super-resolution optical microscopy has greater advantages over the intensity super-resolution optical microscopy for transparent specimens. • Great potential in investigating nanoscale structures, particularly in transparent samples, across various fields such as life sciences, medical diagnostics and defect detection. Phase-contrast optical microscopy technology converts phase variations in transparent specimens into visible intensity variations and has played a pivotal role in the advancement of modern biomedicine. However, most research on phase-contrast microscopes is predominantly based on the Zernike phase-contrast microscope configuration, which employs conventional optics for sample illumination. Therefore, their resolution is fundamentally limited. To further improves the resolution, we propose a super-resolution phase-contrast technique that integrates a super-oscillation illuminating metalens with a phase-plate in a confocal microscope configuration. Experiments demonstrated the proposed super-resolution phase-contrast can resolve a phase-type grating with a linewidth of 120 nm, a pitch of 240 nm, and a phase difference of 0.5π, demonstrating a novel super-resolution phase-contrast microscopy modality. Our method holds great potential in probing nanoscale structures in transparent samples, such as cells and biomedical tissues.