Fig. 4.
Determination of optimal laser power for FFT measurements. The laser power was varied from 0.45 to at the sample level of the 30-mW argon laser. The EGFP solution was set at 20 nM. (a) Plot of molecular brightness as a function of the laser power, measured using either FCS (black squares) or PCH (gray diamonds) methods. (b) Plot of molecular brightness as a function of the laser power based on N&B analysis. (c) and (d) Recovered diffusion coefficients as a function of laser power using FCS or RICS analysis, respectively. All Zeiss LSM 510-ConfoCor 3 settings are the same as in Fig. 2 with the exception of the laser power.