Single shot phase retrieval via Fourier ptychographic microscopy

This paper presents a microscopic phase retrieval method, termed single shot Fourier ptychographic microscopy (SSFPM). SSFPM is devised by combining Fourier ptychographic microscopy (FPM), lens array imaging, and multiplexed illumination. By placing lens array at the Fourier plane of objective lens, multiple intensity profiles required for FPM algorithm are collected in a single shot. To achieve enough redundancy of data for satisfying convergence condition of FPM, specimen is simultaneously illuminated by multiple light emitting diodes (LEDs). Since LEDs lead each intensity profile to be linearly summed, the linearity provides a clue that SSFPM can decompose the combined information. Thus, SSFPM reconstructs quantitative phase profile with sufficient data and simultaneously enhances the resolution which is sacrificed by applying lens array imaging. We demonstrate the performance of SSFPM with numerical simulation and experiments. The prototype achieves lateral resolution of < 2.19 µm over a wide field of view of 0.34 mm$^2$. Without an interferometry, or scanning devices, SSFPM can reconstruct high-resolution of the quantitative phase and intensity profile with a single shot and the system represents comparable performance with conventional bright-field microscope.