Control of plasmonic nanoantennas by reversible metal-insulator transition

TL;DR

This paper demonstrates reversible, nanoscale control of plasmonic nanoantennas using the insulator-metal transition in VO2, enabling ultrafast, local modulation of optical properties for advanced nanophotonic applications.

Contribution

It introduces a method for reversible, localized control of VO2's phase transition to actively manipulate nanoantennas at the nanoscale.

Findings

Reversible control of VO2 phase transition at 15 nm scale.

Real-time near-field imaging of plasmonic changes.

Ultrafast (femtosecond) triggering of phase transition.

Abstract

Nanophotonic (nanoplasmonic) structures confine, guide, and concentrate light on the nanoscale. Advancement of nanophotonics critically depends on active nanoscale control of these phenomena. Localized control of the insulator and metallic phases of vanadium dioxide (VO2) would open up a universe of applications in nanophotonics via modulation of the local dielectric environment of nanophotonic structures allowing them to function as active devices. Here we show dynamic reversible control of VO2 insulator-to-metal transition (IMT) locally on the scale of 15 nm or less and control of nanoantennas, observed in the near-field for the first time. Using polarization-selective near-field imaging techniques, we monitor simultaneously the IMT in VO2 and the change of plasmons on gold infrared nanoantennas. Structured nanodomains of the metallic VO2 locally and reversibly transform infrared plasmonic dipolar antennas to monopole antennas. Fundamentally, the IMT in VO2 can be triggered on femtosecond timescale to allow ultrafast nanoscale control of optical phenomena. These unique capabilities open up exciting novel applications in active nanophotonics.