Plasmon-assisted nanojet lithography

Abstract

The great barrier of optical diffraction significantly limits the resolution of photolithography and the manipulation of nano-objects by light. Here, through utilizing near-field enhancement and photothermal effects, we demonstrate the nanolithography of polystyrene (PS) films and self-jetting of gold nanoparticles (Au NPs), which happen simultaneously. This nanojet lithography creates subwavelength holes via the single step of laser irradiation. We find that the laser power input strongly affects the etching of PS films, as well as the movement of Au NPs, which is a synergic effect of photoablation (including both photothermal and photochemical aspects) and gas pushing. This facile approach not only generates polymer holes with sizes below the diffraction limit, but also provides an intriguing way to detach and move particles on surfaces via thermal jetting.