  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.
