Optical manipulation of charged microparticles in polar fluids.

In this study, we report a systematic study of the response of a charged microparticle confined in an optical trap and driven by electric fields. The particle is embedded in a polar fluid, hence, the role of ions and counterions forming a double layer around the electrodes and the particle surface itself has been taken into account. We analyze two different cases: (i) electrodes energized by a step-wise voltage (DC mode) and (ii) electrodes driven by a sinusoidal voltage (AC mode).