All-optical trapping, relocation, and manipulation of nanoparticles using SOI ring resonators

Abstract

Optical tweezers have opened new doors in microscale research such as single-cell handling and analysis. To develop this technique to nanoscale applications, a number of near-field techniques have been introduced, but they suffer from issues and limitations. Here, we propose simple schemes built by SOI-based optical ring resonators that have efficient trapping and precise transporting functionalities, which are applicable for optical manipulation of nanoparticles. The distribution of the optical intensity excited in a ring resonator and its resultant optical forces on the nanoparticles are calculated numerically. According to the calculations, a subwavelength polystyrene particle as small as 12 nm in radius can be trapped with a depth of 10  kBT by an input power of 10 mW and conveyed to a specified location along the ring with nanometer precision. In addition, we show that the introduced schemes are capable of analyzing physical properties of biostructures such as the binding force of a DNA molecule.