Solid-state far-field macroscopic Fourier ptychographic imaging via programmable illumination with spatial light modulator

Accurate angle-varied illumination can be easily implemented in various ways for Fourier ptychographic microscopy (FPM). However, it is quite challenging at a long distance for far-field macroscopic Fourier ptychography (FP). In this work, we present what we believe to be a novel illumination scheme for macroscopic FP using a spatial light modulator to programmatically modulate the coherent illumination light, which could provide flexible and accurate angle-varied illumination at a relatively long distance. Compared with the existing macroscopic FP illumination methods, it does not need any bulky mechanism to drive laser scanning, thus improving data collection efficiency, and it can also freely adjust the illumination spot size through phase coding to avoid the issues of limited field of view and excessive dispersion of illumination energy. Finally, the illumination scheme is combined with a single camera to form a new solid-state macro FP approach, which is validated experimentally through various everyday objects and USAF targets at lab-scale range. The experimental results confirm its suitability and effectiveness for macro FP imaging.