Researchers have developed a mechanical scanning-free microscopy method. The technique significantly improves the efficacy of fluorescence lifetime microscopy (FLIM).
The fact that fluorescence decay occurs quickly is a major limitation of traditional fluorescence lifetime microscopy methods; most ordinary cameras are incapable of capturing it. Using a single-point photodetector solves the problem, but the device must be scanned over a sample area to create an image with each measured point. The process involves the movement of mechanical parts, which slows down image capture.
The new fluorescence lifetime microscopy method can be thought of as mapping 44,400 light-based’stopwatches’ over a 2D space to measure fluorescence lifetimes in a single shot without scanning. An optical frequency comb is used as the excitation light for the sample; optical frequency combs are light signals composed of the sum of many discrete optical frequencies with a constant spacing between them. The “comb” is a tightly confined cluster of equidistant spikes extending from the optical frequency axis that appears when the signal is plotted against optical frequency.
A pair of excitation frequency comb signals can be decomposed into individual optical beat signals using specialized optical equipment (dual-comb optical beats). These have distinct intensity-modulation frequencies, each with a single modulation frequency irradiating onto a sample.
Related Content: Single-Molecule Localization Microscopy Data Rendering