Simple, stable, compact implementation of frequency-division-multiplexed microscopy by inline interferometry

Frequency-division-multiplexed (FDM) imaging is a powerful method for high-speed imaging that surpasses the speed limit of conventional imaging constrained by the frame rate of image sensors. However, its complexity, instability, and bulkiness deriving from the implementation with a Mach-Zehnder interferometer hamper its practical applications. Here we demonstrate a simple, stable, and compact implementation of FDM imaging by inline interferometry that makes the method readily available to practical situations. As a proof-of-concept demonstration, we demonstrate 2D bright-field and fluorescence image acquisition of fluorescent beads, microalgal cells, and breast cancer cells within 65.5 μs, corresponding to 15,300 frames per second.