TIRF microscopy operates by directing a laser beam at an angle greater than the critical angle for total internal reflection at the interface between two media, typically glass and water. When the light undergoes total internal reflection, an evanescent wave is generated at the interface, which decays exponentially with distance from the surface. This evanescent wave excites fluorophores within a thin region (~100-200 nm) near the surface, allowing for high-contrast imaging of nanoscale structures and processes.
