Scattering intensity from Brownian dynamics: Application to total internal reflection microscopy

Abstract

Total internal reflection microscopy (TIRM) measures the position of a Brownian particle above an interface by using its scattering of an evanescent wave. From the knowledge of the trajectory it is possible to reconstruct the interaction potential between the Brownian particle and the wall with nanometer and femtonewton resolution. TIRM relies on the a priori knowledge of the relation I(z) between the particle position and the scattering intensity. We introduced a method to determine experimentally I(z). Such method largely extends the conditions accessible with TIRM.