Phase and amplitude reconstruction by weak measurement based on metasurface

Phase distribution is crucial for obtaining the whole information of phase object in imaging. However, due to the transparency of phase objects, the phase distribution cannot be obtained in traditional bright-field imaging. Here, we propose a phase distribution reconstruction based on the imaginary value of weak measurement, which is achieved by a Pancharatnam–Berry phase metasurface. Moreover, by adjusting the weak value to a real weak value, amplitude reconstruction can also be achieved. Different parts of weak values can be obtained by controlling the preselection and postselection states. The weak interaction is achieved by the metasurface, which is convenient to control the weak coupling and reduce the complexity of the experimental setup at the same time. Furthermore, the edge contour of objects can also be acquired by the weak measurement, and the edge sharpness is related to types of the weak values, which plays an important role in image resolution. Our method paves a way for quantitative phase imaging and unlabeled biological imaging.