Single-shot quantitative phase imaging based on all-dielectric metasurfaces

Quantitative phase imaging (QPI) is a powerful method for examining label-free biomedical samples. Metasurfaces, which use subwavelength planar structures to precisely manipulate the amplitude, phase, and polarization of light, open up possibilities for novel optical functionalities. By replacing traditional bulky components with metasurfaces, QPI techniques can become simpler and more reliable, thereby enhancing system portability and expanding their use in in vivo imaging. Here, we introduce a single-shot QPI approach by incorporating all-dielectric geometric phase metasurfaces into a conventional microscope. The metasurfaces create two laterally displaced replicas with orthogonal circular polarization states of the input object beam. The interference of the replicas produces a retardance image with bias retardation controlled by an analyzer. The complex amplitude of the object is reconstructed from four retardance images captured simultaneously by a polarization camera. The metasurfaces can be positioned near any conjugate plane of the object, offering a flexible and robust setup for QPI, evincing its broad applicability in live-cell imaging.