Figure 2
From: Multi-frequency passive and active microrheology with optical tweezers
Results from measurements performed with 1 μm-diameter silica beads in water. (a) Trap stiffness \(\kappa _{APC}\) obtained by APC compared with the reference trap stiffness \(\kappa _{PC}\) derived with the PC as a function of the driving frequency. Multi-frequency measurements with prime numbers are compared to consecutive single-frequency measurements. (b) Real part of the friction retardation spectrum \(\gamma '_{APC}\) resulting from single- and multi-frequency APC measurements compared with the theoretical value from Stoke’s law \(\gamma '_{Theo}\).
