Figure 2.

(a) Measured near-infrared permittivity (real part) spectra of the VO₂ film at room temperature (the upper black curve) and 90 °C (the lower red curve). (b) A scheme of the symmetric VIM nanoantenna launching SPPs (t_Au = 50 nm, t_sio2 = 150 nm, t_vo2 = 50 nm). (c) Ey-field profile of the wide symmetric VIM nanoantenna in the insulator phase under incident light of 1650 nm wavelength. (d) IMT-induced amplitude ratio and phase difference between backside SPPs launched in insulator and metal phases according to w_vo2.