Nanophotonic resonators offer the ability to design nanoscale optical elements and engineered materials with unconventional properties. Dielectric-based resonators intrinsically support a complete multipolar resonant response with low absorption, while metallic resonators provide extreme light confinement and enhanced photon-electron interactions. Here, we construct resonators out of a prototypical metal-insulator transition material, vanadium dioxide (VO2), and demonstrate switching between dielectric and plasmonic resonances. We first characterize the temperature-dependent infrared optical constants of VO2 single crystals and thin-films. We then fabricate VO2 wire arrays and disk arrays. We show that wire resonators support dielectric resonances at low temperatures, a damped scattering response at intermediate temperatures, and plasmonic resonances at high temperatures. In disk resonators, however, upon heating, there is a pronounced enhancement of scattering at intermediate temperatures and a substantial narrowing of the phase transition. These findings may lead to the design of novel nanophotonic devices that incorporate thermally switchable plasmonic-dielectric behavior.
|Number of pages||7|
|State||Published - 21 Feb 2018|
Bibliographical noteFunding Information:
We thank Kirk Post and Dmitri Basov for their assistance in temperature-dependent ellipsometry measurements. We are grateful for discussions with Prasad Iyer, Tanya Das, and Steven Brown. This work was supported by the Air Force Office of Scientific Research (Grants FA9550-16-1-0393 and FA9550-12-1-0381) and by the UC Office of the President Multicampus Research Programs and Initiatives (Grant MR-15-328528). Numerical calculations for this work were performed on the computing cluster at the Center for Scientific Computing from the California NanoSystems Institute at the University of California, Santa Barbara, an NSF MRSEC (DMR-1121053) and NSF CNS-0960316. We acknowledge support from the Vannevar Bush Faculty Fellowship program sponsored by the Basic Research Office of the Assistant Secretary of Defense for Research and Engineering and funded by the Office of Naval Research through Grant N00014-15-1-2848. Thin films were prepared at the UCSD Nanoscience Center, and nanostructures were fabricated at the UCSB Nanofabrication Facility. This research was conducted with government support under the DoD, Air Force Office of Scientific Research, National Defense Science and Engineering Graduate (NDSEG) Fellowship, 32 CFR 168a.
© 2017 American Chemical Society.
- metal-insulator transition
- phase change materials
- tunable metasurfaces
- vanadium dioxide