Self-consistent model of light-induced molecular motion around metallic nanostructures

Azobenzene derivatives containing polymers deform when exposed to light with a wavelength in the principle absorption band associated with trans-cis isomerization of the azobenzene derivative molecule. When such polymers cover a metallic nanoparticle exposed to light near its surface plasmon resonance, which also happens to overlap with the azobenzene derivative absorption band, the resulting surface deformations are a novel measure or probe of the plasmonic near-field intensities. We developed a self-consistent model of the process by combining a Monte Carlo based model for the absorption and subsequent light-induced mass transport of the polymer with finite difference time domain computations of the electromagnetic fields around the nanoparticle that induce the absorption. The resulting self-consistent approach is shown to describe the key features of experimental observations concerning silver disk nanoparticles.