An Ultrafast Switchable Terahertz Polarization Modulator Based on III-V Semiconductor Nanowires

Jessica L. Boland, Sarwat A. Baig, Djamshid A. Damry, H. Hoe Tan, Chennupati Jagadish, Hannah J. Joyce, Michael B. Johnston

    Research output: Contribution to journalArticlepeer-review

    Abstract

    Progress in the terahertz (THz) region of the electromagnetic spectrum is undergoing major advances, with advanced THz sources and detectors being developed at a rapid pace. Yet, ultrafast THz communication is still to be realized, owing to the lack of practical and effective THz modulators. Here, we present a novel ultrafast active THz polarization modulator based on GaAs semiconductor nanowires arranged in a wire-grid configuration. We utilize an optical pump–terahertz probe spectroscopy system and vary the polarization of the optical pump beam to demonstrate ultrafast THz modulation with a switching time of less than 5 ps and a modulation depth of −8 dB. We achieve an extinction of over 13% and a dynamic range of −9 dB, comparable to microsecond-switchable graphene- and metamaterial-based THz modulators, and surpassing the performance of optically switchable carbon nanotube THz polarizers. We show a broad bandwidth for THz modulation between 0.1 and 4 THz. Thus, this work presents the first THz modulator which combines not only a large modulation depth but also a broad bandwidth and picosecond time resolution for THz intensity and phase modulation, making it an ideal candidate for ultrafast THz communication.
    Original languageEnglish
    Pages (from-to)2603-2610
    JournalNano Letters
    Volume17
    Issue number4
    Early online date23 Mar 2017
    DOIs
    Publication statusPublished - Apr 2017

    Keywords

    • Terahertz (THz)
    • GaAs
    • nanowire
    • parylene
    • polarizer
    • modulator

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