Figure 1.

Temperature control of the resonances of the antenna–VO₂ hybrids. (a) Helium-ion microscopy images of antenna arrays corresponding to fixed L_v=160 nm and, from bottom to top, L_h=160, 210, 260, 310 and 360 nm. Scale bars, 200 nm. (b) Experimental (left) and calculated (right) extinction spectra (OD) of antenna arrays corresponding to the images of a, for horizontal polarization. The response of the bare VO₂ film and substrate without antennas was subtracted (see Supplementary Information). The sample temperature was set to 30 °C (black lines) and 80 °C (red lines). (c) Temperature hysteresis curve for the OD of bare VO₂ film without antennas, taken at λ_probe=1600 nm. (d) Optical pumping hysteresis curve for bare VO₂, for increasing (black) and decreasing (red) pump energies, taken at repetition rates of 1.0 and 0.1 MHz and a pump wavelength 1060 nm.