Ultrathin tunable terahertz absorber based on MEMS-driven metamaterial

Mingkai Liu*, Mohamad Susli, Dilusha Silva, Gino Putrino, Hemendra Kala, Shuting Fan, Michael Cole, Lorenzo Faraone, Vincent P. Wallace, Willie J. Padilla, David A. Powell, Ilya V. Shadrivov, Mariusz Martyniuk

*Corresponding author for this work

    Research output: Contribution to journalArticlepeer-review

    83 Citations (Scopus)

    Abstract

    The realization of high-performance tunable absorbers for terahertz frequencies is crucial for advancing applications such as single-pixel imaging and spectroscopy. Based on the strong position sensitivity of metamaterials’ electromagnetic response, we combine meta-atoms that support strongly localized modes with suspended flat membranes that can be driven electrostatically. This design maximizes the tunability range for small mechanical displacements of the membranes. We employ a micro-electro-mechanical system technology and successfully fabricate the devices. Our prototype devices are among the best-performing tunable THz absorbers demonstrated to date, with an ultrathin device thickness (~1/50 of the working wavelength), absorption varying between 60% and 80% in the initial state when the membranes remain suspended, and fast switching speed (~27 μs). The absorption is tuned by an applied voltage, with the most marked results achieved when the structure reaches the snap-down state. In this case, the resonance shifts by >200% of the linewidth (14% of the initial resonance frequency), and the absolute absorption modulation measured at the initial resonance can reach 65%. The demonstrated approach can be further optimized and extended to benefit numerous applications in THz technology.

    Original languageEnglish
    Article number17033
    JournalMicrosystems and Nanoengineering
    Volume3
    DOIs
    Publication statusPublished - 2017

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