Interferometric multiplexing for ultrarapid biomedical microscopy

Abstract

Label-free interferometric imaging avoids labelling agents and instead exploits intrinsic optical properties of biological samples, making it a general and unbiased alternative to label-based imaging, particularly when suitable exogenous markers are unknown or unavailable. By providing quantitative phase and refractive index information, it reveals structural and functional features often missed by conventional imaging, enabling new diagnostic opportunities. Off-axis interferometric multiplexing is an unconventional label-free imaging approach involving simultaneously capturing of several complex wavefronts, each encoded with a different interference fringe orientation, using a single camera exposure. This enables high-speed imaging of dynamic samples, with applications including tomographic phase microscopy, multi-wavelength imaging, super-resolution, birefringence measurement, and combined phase–fluorescence imaging. I will review this field theory, various optical systems, specific applications, and perspectives.