Electrokinetic patterning of colloidal particles with optical landscapes

We demonstrate an opto-electrokinetic technique for noninvasive particle manipulation on the surface of a parallel-plate indium tin oxide (ITO) electrode that is biased with an alternating current (AC) signal and illuminated with near-infrared (1064 nm) optical landscapes. This technique can generate strong microfluidic vortices at higher AC frequencies (> 100 kHz) and dynamically and rapidly aggregate and pattern particle groups at low frequencies (< 100 kHz).