Voltage-controlled active mid-infrared plasmonic devices

We demonstrate active voltage-controlled spectral tuning of mid-infrared plasmonic structures. Extraordinary optical transmission gratings were fabricated on n-doped GaAs epilayers with a HfO2 gate dielectric between the grating and the doped semiconductor. The permittivity of the GaAs was tuned by depleting charge carriers below the top grating gate upon the application of a reverse bias to the gate. Devices were characterized both electrically and optically, and resonant transmission peak spectral and transmitted intensity shifts were achieved. Possible applications for, as well as the limitations of, the demonstrated technology are discussed.