2023 Departmental Poster Competition

Vanadium dioxide (VO2) undergoes a reversible insulator-to-metal phase transition (IMT) near room temperature, providing an active tunable platform for photonics devices due to drastic change in VO2 optical properties at IMT. A high-quality VO2 film on a Gallium Arsenide (GaAs) substrate is significant in photonics applications for the development of electrically and thermally tunable devices operating at far-infrared (FIR) spectral range. VO2 film on GaAs will be an attractive platform to develop phonon polaritonic metasurfaces because GaAs support phonon polaritons at its FIR Reststrahlen band (28.5 – 33 µm). In this work, we numerically demonstrate thermally tunable surface phonon polaritonic devices using VO2 films on GaAs, working within GaAs’s Reststrahlen band.  The device consists of 40 nm thick gold grating (periodicity = 1100 nm, gap = 100 nm) on 100 nm thick VO2 on GaAs substrate. The cavity resonance is observed near 30.2 µm and shows redshifts as temperature increases. Furthermore, we explore various grating periods and gaps to control the cavity resonance tuning and its dynamic redshift induced by temperature changes.