The Photonic Force Microscope and Its Applications

The ability of detecting forces and torques at the micro- and nano- scale is of fundamental importance. The photonic force microscope (PFM) had been employed to measure forces in the range of femto- to pico-Newton in many di¿erent ¿elds with exciting applications in biophysics, thermodynamics of small systems, and colloidal physics. Here, after an introductive overview of a typical PFM setup, we discuss the three main aspects necessary to understand the PFM, i.e. optical trapping, Brownian motion in an optical trap, and position detection. In the second part of the book, we describe some applications of the PFM: the measurement of plasmon radiation forces, the photonic torque microscope and the measurement of the torque produced by a vortex light beam, the measurement of the characteristics of microscopic ¿ows, and some applications with trapped cells.