We investigate optical forces on oscillating dipoles close to a phase-change vanadium dioxide (VO2) film, which exhibits a metal-insulator transition around 340 K and low thermal hysteresis. This configuration is related to one composed of an excited two-level quantum emitter and we employ a classical description to capture important aspects of the radiation-matter interaction. We consider both electric and magnetic dipoles for two different configurations, namely, with the dipole moments parallel and perpendicular to the VO2 film. By using Bruggeman theory to describe the effective optical response of the material, we show that, in the near-field regime, the force on the dipoles can change from attractive to repulsive just by heating the film for a selected frequency range. We demonstrate that the thermal hysteresis present in the VO2 transition clearly shows up in the behavior of the optical forces, setting the grounds for alternative approaches to control light-matter interactions using phase-change materials.
@article{arxiv.2105.02493,
title = {Optical forces on an oscillating dipole near VO$_2$ phase transition},
author = {Daniela Szilard and Patrícia P. Abrantes and Felipe A. Pinheiro and Felipe S. S. Rosa and Carlos Farina and Wilton J. M. Kort-Kamp},
journal= {arXiv preprint arXiv:2105.02493},
year = {2021}
}