Wide-field, high-resolution Fourier ptychographic microscopy

Abstract

We report an imaging method, termed Fourier ptychographic microscopy (FPM), which iteratively stitches together a number of variably illuminated, low-resolution intensity images in Fourier space to produce a wide-field, high-resolution complex sample image. By adopting a wavefront correction strategy, the FPM method can also correct for aberrations and digitally extend a microscope's depth of focus beyond the physical limitations of its optics.As a demonstration, we built a microscope prototype with a half-pitch resolution of 0.78 µm, a field of view of ∼120 mm2 and a resolution-invariant depth of focus of 0.3 mm (characterized at 632 nm). Gigapixel colour images of histology slides verify successful FPM operation. The reported imaging procedure transforms the general challenge of high-throughput, high-resolution microscopy from one that is coupled to the physical limitations of the system's optics to one that is solvable through computation. A wide-field, high-resolution imaging scheme that offers enhanced depth of field is demonstrated. The approach relies on stitching together time-multiplexed images in Fourier space.