Miniaturized high-resolution Fourier ptychographic microscopy based on fiber optic array

Abstract

Fourier ptychographic microscopy (FPM) is a computational imaging method that reconstructs high-resolution images by synthesizing multiple low-resolution images captured under varying illumination angles. In this work, we propose a miniaturized FPM based on the fiber optic array (FOA, 6×, $\mathrm{NA}=0.65$) which can improve the resolution from 9.84 μm to 1.74 μm compared to conventional objective (10×, $\mathrm{NA}=0.25$)-based FPM. The FOA enables distortion-free microscopy imaging, while a programmable LED array provides the angular illumination required for FPM recovery and synthetic aperture generation. The system couples the FOA to the smartphone’s built-in camera for microscopy imaging. Furthermore, by employing a hybrid FOA-Lens FPM (FOA, lens and FPM, termed FLFPM), the resolution is enhanced to 775 nm. Within a consistent field of view of 92 μm × 185 μm, there is no visible naked-eye distortion. Line-pair grayscale profile analysis was performed on all resolution images to provide additional evidence that the selected line pairs are distinguishable. Moreover, we investigated the resolution performance of various configurations, including the FOA-only mode, the FOA-FPM mode, and the FLFPM. To quantify performance, we compared the signal-to-background ratio (SBR) of these systems. The FLFPM demonstrated the highest contrast, indicating superior background suppression and signal extraction. This advantage was further confirmed by Modulation Transfer Function (MTF) analysis, where the FLFPM achieved the highest spatial frequency (592.90 lp/mm) at a 0.7 contrast threshold. This method provides a hardware improvement approach for enhancing the resolution of FPM.