  We investigate the dynamics of single microparticles immersed in water that
are driven out of equilibrium in the presence of an additional external colored
noise. As a case study, we trap a single polystyrene particle in water with
optical tweezers and apply an external electric field with flat spectrum but a
finite bandwidth of the order of kHz. The intensity of the external noise
controls the amplitude of the fluctuations of the position of the particle, and
therefore of its effective temperature. Here we show, in two different
nonequilibrium experiments, that the fluctuations of the work done on the
particle obey Crooks fluctuation theorem at the equilibrium effective
temperature, given that the sampling frequency and the noise cutoff frequency
are properly chosen. Our experimental setup can be therefore used to improve
the design of microscopic motors towards fast and efficient devices, thus
extending the frontiers of nano machinery.
