Publications associated with Terahertz Photonics


An ultrafast switchable terahertz polarization modulator based on III--V semiconductor nanowires

Nano Letters American Chemical Society 17 (2017) 2603–2610-

SA Baig, JL Boland, DA Damry, HH Tan, C Jagadish, HJ Joyce, M Johnston

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 realised, 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 utilise 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 -8dB. We achieve extinction of over 13% and dynamic range of -9dB, 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 0.1THz and 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.


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