Modulated optical transmission of subwavelength hole arrays in metal-VO2 films

We demonstrate the modulation of the transmission of near-infrared light through a periodic array of subwavelength apertures in Ag-VO2 and Au-VO2 double-layer films using the semiconductor-to-metal phase transition in VO2. The transmitted intensity ratio increases by a factor of 8 as the VO2 goes from the semiconductor to the metal phase. We attribute this modulation to the switchable dielectric-permittivity contrast between the air-filled holes in the array and the surrounding VO2 material, a conjecture that is semiquantitatively confirmed by simulation.