Resolution improvement of optoelectronic tweezers using patterned electrodes

An optoelectronic tweezer (OET) device is presented that exhibits improved trapping resolution for a given optical spot size. The scheme utilizes a pair of patterned physical electrodes to produce an asymmetric electric field gradient. This, in turn, generates an azimuthal force component in addition to the conventional radial gradient force. Stable force equilibrium is achieved along a pair of antipodal points around the optical beam. Unlike conventional OETs where trapping can occur at any point around the beam perimeter, the proposed scheme improves the resolution by limiting trapping to two points. The working principle is analyzed by performing numerical analysis of the electromagnetic fields and corresponding forces. Experimental results are presented that show the trapping and manipulation of micro-particles using the proposed device.

Automated summary

This article introduces an optoelectronic tweezer (OET) device that provides improved trapping resolution for a given optical spot size. The device uses patterned physical electrodes to create an asymmetric electric field gradient, resulting in an additional azimuthal force component along with the conventional radial gradient force. The device achieves stable force equilibrium at a pair of antipodal points surrounding the optical beam. Unlike conventional OETs, which allow trapping at any point around the beam perimeter, this scheme enhances resolution by limiting trapping to two points. The working principle is analyzed through numerical analysis of electromagnetic fields and corresponding forces. Experimental results demonstrate successful trapping and manipulation of micro-particles using the proposed device.