Philip H. Jones, Onofrio M. Maragò & Giovanni Volpe
Fig. 9.12 — Autocorrelation analysis
Autocorrelation analysis. Position autocorrelation functions (ACFs) corresponding to a polystyrene sphere (a = 1.03 μm) optically trapped with 2.3, 6.0 and 10.8 mW laser power (λ0 = 1064 nm) at the sample. The symbols and error bars are the experimental ACFs [Eqs. (9.33)] and the solid lines are the theoretical ACFs [Eq. (9.32)] corresponding to the fitted parameters. The fitted values of the stiffness are κx(ex) = 14.1 ± 0.4, 36.0 ± 1.0 and 68.9 ± 1.0 fN/nm and those of the unit conversion factor [Eq. (9.31)] are Sx(ex) = 480, 192 and 107 nm/V. As can be clearly seen, the stronger the trap, the faster the decay of the ACF.