Scientists from the Institute of Post-Led Photonics, Tokushima University develop a fluorescence 'lifetime' microscopy technique that uses frequency combs and no mechanical parts to observe dynamic biological phenomena. Fluorescence microscopy is widely used in biochemistry and life sciences because it allows scientists to directly observe cells and certain compounds in and around them. Fluorescent molecules absorb light within a specific wavelength range and then re-emit it at the longer wavelength range. However, the major limitation of conventional fluorescence microscopy techniques is that the results are very difficult to evaluate quantitatively; fluorescence intensity is significantly affected by both experimental conditions and the concentration of the fluorescent substance. A way around the conventional problem is to focus on fluorescence lifetime instead of intensity. When a fluorescent substance is irradiated with a short burst of light, the resulting fluorescence does not disappear immediately but actually "decays" over time in a way that is specific to that substance. The 'fluorescence lifetime microscopy' technique leverages this phenomenon which is independent of experimental conditions to accurately quantify fluorescent molecules and changes in their environment.