Active Modulation of Plamon-Induced Transparency in Gold:VO$_{2}$ Hybrid Nanostructures

Plasmon-induced transparency (PIT) is a classical analogue of electromagnetically induced transparency where a spectrally broad and a spectrally narrow plasmon resonance interact. This interaction can yield a sharp, narrow increase in transmission referred to as a transparency window. Here we demonstrate a novel method of reversibly and actively modulating the plasmon resonance of~multi-element plasmonic nanostructures which exhibits PIT by using the phase transition in vanadium dioxide. Vanadium dioxide (VO$_{2})$ modulates the near-field dielectric environment of metal nanostructures via its semiconductor-to-metal transition (SMT). The SMT shifts the plasmonic response of the metal nanostructure. We design these hybrid structures using three-dimensional, finite-difference time-domain (FDTD) simulations and fabricate them with a combination of high-resolution electron-beam lithography and VO$_{2}$ deposition. To measure the modulation, we use IR spectroscopy and observe the spectral change in the location of the PIT window as we heat the VO$_{2}$ to thermally induce the phase transition. As the SMT can also be induced optically, these hybrid structures could be useful nanoscale switches or sensors.