Multidimensional multiplexing metalens for STED microscopy

Stimulated emission depletion (STED) microscopy is a versatile super-resolution imaging technique for life sciences and data storage. Despite continuous breakthroughs, modern STED microscopes are still relatively bulky and limited to laboratory setups. Here, we exploit the multidimensional multiplexing properties of metalenses and experimentally demonstrate the realization of a compact STED lens with a single metasurface. A 635-nm right-handed circularly polarized excitation laser is focused by the metalens into a diffraction-limited Gaussian beam, while a 780-nm depletion beam with opposite chirality is converted into a high-quality donut-shaped focus on the same plane. As a consequence, STED super-resolution imaging based on the metalens has been obtained by recording the unpolarized photoluminescence using the same metalens. The experimentally demonstrated resolution reaches 0.7× of the diffraction limit and can be further improved. This study represents a critical step toward the miniaturization and integration of STED microscope.