Multimodal phase microscopy via differential metasurface

Quantitative phase microscopy (QPM) has been an effective technique to examine stain-free biomedical tissues and cells. The development of simple and compact QPM technology with planar optical components enhances system integration and portability. Here, we propose a QPM technique by inserting a metasurface-assisted optical differential system to replace the bulky optical elements in the conventional microscope. The differential scheme allows for the separation of amplitude and phase information for a complex field, offering an opportunity to quantitatively analyze the phase distribution of samples. The experimental demonstrations showcase the well-executed application of the proposed method to artificial phase samples, paramecium cells, fishtail cross-cut tissue, and diatom cells. Notably, our imaging system allows switching between four imaging modes—brightfield, optical spatial differential, differential interference contrast, and QPM. At a high level, this work may drive the advancement of single-shot and multi-mode integrated phase microscopy for biomedical imaging and diagnostics.