Thermochromic modulation of surface plasmon polaritons in vanadium dioxide nanocomposites

Abstract

We propose and implement a new concept for thermochromic plasmonic elements. It is based on vanadium dioxide (VO₂) nanocrystals located in the near field of surface plasmon polaritons supported by an otherwise unstructured gold thin film. When the VO₂ undergoes the metal-insulator phase transition, the coupling conditions for conversion of light into propagating surface plasmon polaritons change markedly. In particular, we realize thermochromic plasmonic grating couplers with substantial switching contrast as well as tunable plasmonic couplers in a Kretschmann configuration. The use of VO₂ nanocrystals permits highly repetitive switching and room temperature operation. Simulations based on the actual dielectric function of our VO₂ nanocrystals agree well with the experiment.

Correlation between in situ structural and optical characterization of the semiconductor-to-metal phase transition of VO2 thin films on sapphire

“…In this section we show the infrared radiometric measurements performed upon phase transition on the different VO 2 thin films deposited on the sapphire substrate. The analysis has been performed in both the SWIR range (2.5-5 µm) and LWIR range (8)(9)(10)(11)(12) µm) by using the equipments described in section 2.3.…”

“…[3][4][5] Among the PCMs, vanadium dioxide (VO 2 ) is definitely one of the most promising materials and is finding application in a continuously growing number of different fields. [6][7][8][9][10][11][12][13] Discovered for the first time by Morin in 1959, 14 VO 2 is characterized by a reversible, first-order semiconductor-to-metal phase transition (SMT), which occurs right above room temperature (at about 68 • C). Upon the SMT, the material switches from the semiconductor state (with a monoclinic crystallographic structure) to the metallic state (tetragonal, rutile structure), changing drastically its electrical properties (electrical conductivity may change up to The change of physical properties in vanadium dioxide during the phase transition is also characterized by an hysteresis loop whose temperature width varies from few degrees (2-3 • C) in single crystals, up to few tens of degrees (10-40 • C) in thin films containing small nanocrystals with different sizes.…”

Enhanced Thermochromic Properties of Vanadium Dioxide (VO2)/Glass Heterostructure by Inserting a Zr-Based Thin Film Metallic Glasses (Cu50Zr50) Buffer Layer

“…The appearance of the SPPs probably effectively modulates the optical properties. This mechanism will be further studied in the future [38,39]. When increasing the Cu50Zr50 buffer layer thickness to 160 nm, the ΔTsol and ΔT2500nm values clearly decreased.…”

Active Control of Surface Plasmon–Emitter Strong Coupling

“…The WS 2 exciton is spectrally sensitive to the temperature variation. of refractive index has been used to switch the plasmon resonances in, for instance, gold thin film accompanied by VO 2 nanocrystals, 54 Ag-VO 2 bilayers, 55 and gold nanorods on VO 2 thin film. 56 Note that in the metal phase the VO 2 supports surface plasmon resonances itself.…”