Photon-Efficient, Hybrid Illumination for High-Throughput Fourier Ptychographic Phase Microscopy Using Lenslet-Integrated LED Illuminator

Abstract

Fourier ptychographic microscopy (FPM) is a computational microscopy platform capable of large-area, high-resolution imaging of thin specimens. FPM enhances the spatial resolution beyond the diffraction limit of the objective by synthesizing frequency information from multiple images captured at various illumination angles. However, this enhancement comes at the cost of temporal resolution, making conventional FPMs unsuitable for imaging dynamic samples. The low temporal resolution of FPM is mainly attributed to two factors: the large number of measurements required for resolution improvement and the long exposure time, particularly in capturing dark-field (DF) images. Here, a novel high-throughput FPM strategy, termed PEH-FPM, enabled by the combination of photon-efficient, lenslet-array-integrated LED illuminator, and a hybrid multiplexed-illumination scheme is introduced. The illuminator provides vignette-free, high-intensity illumination at the object plane, thereby dramatically reducing the DF acquisition time to a few milliseconds and eliminating vignetting-induced artifacts present in conventional FPM approaches. The illumination-multiplexing scheme significantly reduces the number of measurements, achieving a 0.51-NA resolution across a field of view of 4.1 mm2 with a total acquisition time of 21-40 msec, using 4 x 0.13NA objective. The imaging platform is expected to find numerous applications that call for dynamic, high-resolution imaging over a large spatial scale.