Near‐Infrared Metalens Empowered Dual‐Mode High Resolution and Large FOV Microscope

Abstract The spiral phase contrast microscope can clearly distinguish the morphological information of the low contrast objects (i.e., biological samples) owing to the isotropic edge‐enhancement effect, while the bright field microscope can image the overall morphology of amplitude objects. However, the imaging resolution, magnification, and field of view of conventional spiral phase contrast microscopes based on 4f filtering configuration are limited by the system's complexity. Here, compact dual‐mode microscopes working at near‐infrared using the engineered metalens are reported, which can be tuned between the spiral phase contrast imaging and bright field imaging by polarization control. The metalens combine the high‐resolution objective lens and polarization‐controlled phase filter into a single‐layer nanofins array. Two infinity‐corrected microscope systems are demonstrated to achieve subwavelength resolution (0.7λ), large magnification (58X), and large field of view (600 × 800 µm). Unstained onion epidermal is imaged by the microscope to show the dual‐mode imaging ability for the biological sample. Finally, a singlet dual‐mode microscope system is demonstrated to show the edge‐detection application for industrial standards. These results can open new opportunities in applications of biological imaging, industrial machine vision, and semiconductor inspection.