Figure 6.

Simulated autocorrelation curves at varying mesh diameters a and constant FCS detection spot area of ω = 250 nm. (A and B) Two examples with difference in confinement are shown. In both plots the autocorrelation curves from left to right were simulated with decreasing mesh diameter and by using the same set of Voronoi meshes. The leftmost curves were obtained with a mesh larger than the FCS detection area, for the middle curves mesh and detection area were similar, and the right curves were simulated with a mesh smaller than the detection area (from left to right: ω/a = 0, 0.5, 0.9, 1.1, 2.1, 3.1). In both cases a transition from fast single-component microscopic diffusion (diffusion inside the mesh) over an intermediate regime to slower macroscopic diffusion (diffusion on scales larger than the mesh) occurs. (A) Autocorrelation curves simulated at comparably weak confinement (p_jump = 0.1). With decreasing mesh diameter the decay of the autocorrelation curve is shifted toward longer correlation times. (B) Autocorrelation curves simulated at stronger confinement (p_jump = 0.01). In this case, a clear deviation from single-component diffusion at mesh diameters comparable to the detection spot size is evident, due to the shape of the autocorrelation curves.