Photothermal reshaping of gold nanoparticles in a plasmonic absorber.

We experimentally demonstrate that a metamaterial nanostructure can have a localized heating response owing to plasmonic resonances in the near-infrared wavelength range (from 1.5 to 2 µm). With a broadband nanosecond-pulse light, the temperature of composing gold particles in the nanostructure can be easily increased to over 900K within only several nanoseconds, resulting in re-shaping of the particles. The photothermal effect is elaborated with finite-element based numerical simulations. The absorption resonance can in principle be tailored with a great freedom by choosing appropriate metamaterial parameters. The light-induced heating in an artificial metamaterial can be potentially used for all-optical acute temperature tuning in a micro-environment, which may open new frontiers especially in nanotechnology and biotechnology.