Dynamically tunable bowtie nanoantennas based on the phase transition of vanadium dioxide

The plasmonic nanoantenna has attracted intensive attention over the last decades owing to its unique optical response. Although various nanoantennas have been designed, so far very few efforts have been devoted to their dynamic tunability. Here we present a study on dynamically tunable bowtie nanoantennas integrated on a vanadium dioxide thin film with a thermal phase transition. The insulator-metal transition of vanadium dioxide changes its electric feature and permittivity; hence, the resonance of the bowtie nanoantennas is actively tuned by varying the temperature of the device. Further, by adjusting the gap of the bowtie and the edge size of the nanotriangle at a different temperature, the shift of the resonant wavelength of the nanoantenna has been found to increase for a larger triangle edge size, but less dependent on the gap width. The features suggest that VO2-integrated nanoantennas may have applications in dynamically tunable high-harmonic generation, single-molecule fluorescence enhancement, and nanolasers. (C) 2019 Optical Society of America