Light-actuated digital microfluidics for large-scale, parallel manipulation of arbitrarily sized droplets

We report on a new light-actuated digital microfluidics device which is capable of using on demand, `virtual' electrodes formed by a data projector to enable large-scale, parallel manipulation of arbitrarily sized droplets. The device features a thin, high-quality Al
₂
O
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film deposited via atomic layer deposition (ALD) which allows aggressive scaling of the dielectric thickness, while maintaining high device reliability. We demonstrate the splitting, merging and parallel manipulation of droplets at high actuation speeds (2 cm/s). Due to the thin ALD dielectric layer, this high actuation speed is achieved at 85x lower optical power and 5x lower voltage than our previous device.