Fluorescence interferometry: From mesoscopic to nanoscopic biomedical imaging

The use of low-level light radiation, such as fluorescence, is central for tackling measurement problems in biology and medicine with high sensitivity and at high, multidimensional optical resolution. Typically, the intensity of low-level light waves is utilized and simply measured by ultra-sensitive detection systems. Nevertheless, the phase of a these optical waves contains subtle, but no less important, information about the observed medium; yet, it has been largely unexplored. Here, we introduce the concept of fluorescent light interferometry to open up new possibilities for measuring fluorescence phase information through biological matter with nanometer-to-mesoscopic level resolution.