Optical properties of subwavelength hole arrays in vanadium dioxide thin films

Abstract

We demonstrate that the transmission of far-and near-field incident light through a periodic array of subwavelength holes in a vanadium-dioxide ͑VO 2 ͒ thin film is enhanced in the infrared range with respect to transmission through the unperforated film when VO 2 undergoes its semiconductor-to-metal transition. We explain this enhancement by analyzing the loss of transmitted intensity due to leaky evanescent waves inside the holes and scattering at the entrance and exit apertures. Numerical simulations based on the transfer-matrix formalism provide qualitative support for the model and reproduce the principal features of the experimental measurements.

Ultrafast optical switching of the THz transmission through metallic subwavelength hole arrays

“…Switching has also been demonstrated by utilizing the metal-insulator transition in vanadium oxide hole arrays. 22 Optical control of THz transmission has been demonstrated for a semiconductor hole array, 23 where photoexcitation using a high repetition rate pulsed laser source resulted in a steady buildup of surface charge densities and presumably a modification of surface modes. All of these control techniques are, however, inapplicable when fast switching is required.…”

Using a Semiconductor‐to‐Metal Transition to Control Optical Transmission through Subwavelength Hole Arrays

“…Two types of structures investigated in [8,9] were: (i) hole array in Ag-on-VO 2 double layer on glass ( Figure 1 diameter ≈ 100 nm). It is relevant to note here that the airfilled holes in this SNOM image appear darker, that is, transmit less than the surrounding VO 2 film, whereas the contrast is reversed in the case of holes in Ag-VO 2 (Figure 1(e)) or Au-VO 2 double layers (not shown).…”

“…In order to bring out the significance of the VO 2 layer for the metallic-phase enhancement of the EOT in Ag-VO 2 -SiO 2 and Au-VO 2 -SiO 2 structures, the optical properties of a hole array in VO 2 on glass (Figure 1(c)), that is, without a goodmetal overlayer, were also examined [9]. It must be noted that transmission observed through this type of structure is not extraordinary, in the sense used thus far, owing to the insufficient opacity of the VO 2 layer.…”

“…Here we review another recently demonstrated method to control the amount of light transmitted through perforated double-layer thin films on transparent substrates [8,9]. The structures consist of an optically opaque metal film (silver or gold) on top of a vanadium dioxide (VO 2 ) film deposited on a glass (SiO 2 ) substrate, with a periodic array of subwavelength holes penetrating the double layer.…”

Transmission increase upon switching of VO2 thin films on microstructured surfaces

“…4 Optical switching in VO 2 has extensively been studied in thin films, 5 nanoparticles, 6 nanoparticle arrays, 7 and subwavelength nanohole arrays. 8 However, relatively little attention has been paid to thin-film micro-or nanostructures of VO 2 , even though optically switchable nanostructures are attractive for photonic applications. In this letter, we use transmission measurements through VO 2 thin films and thin films deposited on ordered arrays of spherical silica ͑SiO 2 ͒ microspheres to show how the zeroth-order ͑"straight through"͒ transmission can be altered by substrate microstructure.…”