Abstract:
Seeing individual molecules with Raman spectroscopy requires very intense optical fields. An arrangement of metal nanoparticles can provide the necessary boost. Researchers in the USA and Israel have devised a 'nanolens' capable of enhancing the strength of an optical field by a factor of a thousand or so. They show that arrangements of a few metal nanoparticles can generate the lensing effect, creating a small local hotspot of field intensity1. This hotspot could be used for single-molecule spectroscopy and for manipulation of nanoscale and molecular objects using optical tweezers.