Torque detection using Brownian fluctuations
Giovanni Volpe & Dmitri Petrov
Physical Review Letters 97(21), 210603 (2006)
We report the statistical analysis of the movement of a submicron particle confined in a harmonic potential in the presence of a torque. The absolute value of the torque can be found from the auto- and cross-correlation functions of the particle’s coordinates. We experimentally prove this analysis by detecting the torque produced onto an optically trapped particle by an optical beam with orbital angular momentum.
Also featured in “Focus: Hidden Twists and Turns”, Physics 18, 17 (December 1, 2006)