Plasmonic nanotweezers trap tightly without overheating
September 28, 2011
Harvard engineers have created “plasmonic nanotweezers” that use laser light to trap and study nanoparticles such as viruses more efficiently than optical tweezers, without overheating.
With optical tweezers, a lens cannot focus the beam any smaller than half the wavelength of the light; the focal size limit places an upper limit on the gradient force that can be generated; and they overheat. The new design uses plasmonics for tighter focusing, along with silicon coated in copper and then gold, with raised gold pillars, acting as a heat sink.
Ref.: Kai Wang, et al., Trapping and rotating nanoparticles using a plasmonic nano-tweezer with an integrated heat sink, Nature Communications, 2011; [DOI:10.1038/ncomms1480]