Phase sensitive VO2-metal switchable plasmonic metasurface for thermal controlling of broad band near-infrared absorption

An absorptive switchable plasmonic metasurface is proposed and numerically investigated using FDTD computation to achieve thermally controllable optical absorption in the broad spectral window from 800 to 1500 nm. Typical metasurface unit cell is composed of phase sensitive vanadium dioxide (VO2) ring and co-axial gold sphere placed on a flat ground gold plane. Phase change of VO2 from metallic to semiconducting state or vice versa results in observable contrast in the absorption strength Delta A of similar to 0.2 in the spectral range > 850 nm. The absorption contrast remains high, and is not significantly affected by the passive change in the structural period (500-700 nm), types of metals (gold, silver, aluminum) and excitation launch angle (up to similar to 20 degrees) indicating favourable design flexibility associated with the proposed structure. Polarization insensitivity, large launch angle tolerance and high absorption contrast make this novel metasurface suitable for optoelectronic device integration for dynamic controlling of near-infrared absorption and switching operation.

Automated summary

An absorptive switchable plasmonic metasurface has been proposed for thermally controllable optical absorption in the broad spectral window from 800 to 1500 nm. The metasurface unit cell consists of vanadium dioxide (VO2) ring and co-axial gold sphere, allowing for a significant absorption contrast in the spectral range > 850 nm. The structure shows high absorption contrast, flexibility in design, and is suitable for optoelectronic device integration.