Control of plasmonic nanoantennas by reversible metal-insulator transition

We demonstrate dynamic reversible switching of VO(2) insulator-to-metal transition (IMT) locally on the scale of 15 nm or less and control of nanoantennas, observed for the first time in the near-field. Using polarization-selective near-field imaging techniques, we simultaneously monitor the IMT in VO(2) and the change of plasmons on gold infrared nanoantennas. Structured nanodomains of the metallic VO(2) locally and reversibly transform infrared plasmonic dipole nanoantennas to monopole nanoantennas. Fundamentally, the IMT in VO(2) can be triggered on femtosecond timescale to allow ultrafast nanoscale control of optical phenomena. These unique features open up promising novel applications in active nanophotonics.