Development of opto-electro static micro-pump using a focused laser in a high-frequency electric field

Micropump driven by laser irradiation in high-frequency electric field was demonstrated We discovered an opto-electrostatical phenomenon called as opto-electrostatic micro vortex (OEMV) (A. Mizuno, et al, 1995). The OEMV was generated around a laser focal point placed at center of an intense high-frequency electric field in water solution. The direction of the flow was from the laser point towards both of the ac electrodes. In this research, the laser point was placed near one electrode. A flow occurred toward the other electrode. We applied OEMV to generate fluid flow in microchannel as opto-electrostatic micro-pump. The microchannel was fabricated on polydimethylsiloxane (PDMS) sheet. The PDMS sheet was mounted on the glass plate on which the electrodes were patterned. When a Nd:YAG laser (1064 nm, cw) and ac voltage at 1 MHz was applied, fluid flow occurred. The flow velocity increased linearly with magnitude of the laser power and the ac voltage. The flow velocity around the focal point was several hundreds μm/sec. At the position 3 mm apart from the laser spot, flow velocity was 25 μm/sec (0.74 μl/sec).