Near-field enhanced optical tweezers utilizing femtosecond-laser nanostructured substrates

TL;DR

This paper demonstrates plasmonic-enhanced optical tweezers using nanostructured metal substrates, showing improved trapping forces and heat management, with potential applications in precise particle manipulation.

Contribution

It introduces a novel near-field optical trapping method utilizing femtosecond-laser nanostructured substrates with heat dissipation improvements.

Findings

Enhanced trapping force near nanostructures

Exponential distance dependence of trapping force

Effective heat dissipation with Cu/Au bilayer

Abstract

We present experimental evidence of plasmonic-enhanced optical tweezers, of polystyrene beads in deionized water in the vicinity of metal-coated nanostructures. The optical tweezers operate with a continuous wave (CW) near-infrared laser. We employ a Cu/Au bilayer that significantly improves dissipation of heat generated by the trapping laser beam and avoid de-trapping from heat convection currents. We investigate the improvement of the optical trapping force, the effective trapping quality factor, and observe an exponential distance dependence of the trapping force from the nanostructures, expected from the evanescent plasmon field.