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Proceedings Paper

Fast terahertz optoelectronic amplitude modulator based on plasmonic metamaterial antenna arrays and graphene
Author(s): David S. Jessop; Christian W. O. Sol; Long Xiao; Stephen J. Kindness; Philipp Braeuninger-Weimer; Hungyen Lin; Jonathan P. Griffiths; Yuan Ren; Varun S. Kamboj; Stephan Hofmann; J. Axel Zeitler; Harvey E. Beere; David A. Ritchie; Riccardo Degl'Innocenti
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Paper Abstract

The growing interest in terahertz (THz) technologies in recent years has seen a wide range of demonstrated applications, spanning from security screening, non-destructive testing, gas sensing, to biomedical imaging and communication. Communication with THz radiation offers the advantage of much higher bandwidths than currently available, in an unallocated spectrum. For this to be realized, optoelectronic components capable of manipulating THz radiation at high speeds and high signal-to-noise ratios must be developed. In this work we demonstrate a room temperature frequency dependent optoelectronic amplitude modulator working at around 2 THz, which incorporates graphene as the tuning medium. The architecture of the modulator is an array of plasmonic dipole antennas surrounded by graphene. By electrostatically doping the graphene via a back gate electrode, the reflection characteristics of the modulator are modified. The modulator is electrically characterized to determine the graphene conductivity and optically characterization, by THz time-domain spectroscopy and a single-mode 2 THz quantum cascade laser, to determine the optical modulation depth and cut-off frequency. A maximum optical modulation depth of ~ 30% is estimated and is found to be most (least) sensitive when the electrical modulation is centered at the point of maximum (minimum) differential resistivity of the graphene. A 3 dB cut-off frequency > 5 MHz, limited only by the area of graphene on the device, is reported. The results agree well with theoretical calculations and numerical simulations, and demonstrate the first steps towards ultra-fast, graphene based THz optoelectronic devices.

Paper Details

Date Published: 25 February 2016
PDF: 14 pages
Proc. SPIE 9747, Terahertz, RF, Millimeter, and Submillimeter-Wave Technology and Applications IX, 97471E (25 February 2016); doi: 10.1117/12.2210984
Show Author Affiliations
David S. Jessop, Univ. of Cambridge (United Kingdom)
Christian W. O. Sol, Univ. College London (United Kingdom)
Long Xiao, Univ. of Cambridge (United Kingdom)
Stephen J. Kindness, Univ. of Cambridge (United Kingdom)
Philipp Braeuninger-Weimer, Univ. of Cambridge (United Kingdom)
Hungyen Lin, Lancaster Univ. (United Kingdom)
Jonathan P. Griffiths, Univ. of Cambridge (United Kingdom)
Yuan Ren, Univ. of Cambridge (United Kingdom)
Varun S. Kamboj, Univ. of Cambridge (United Kingdom)
Stephan Hofmann, Univ. of Cambridge (United Kingdom)
J. Axel Zeitler, Univ. of Cambridge (United Kingdom)
Harvey E. Beere, Univ. of Cambridge (United Kingdom)
David A. Ritchie, Univ. of Cambridge (United Kingdom)
Riccardo Degl'Innocenti, Univ. of Cambridge (United Kingdom)

Published in SPIE Proceedings Vol. 9747:
Terahertz, RF, Millimeter, and Submillimeter-Wave Technology and Applications IX
Laurence P. Sadwick; Tianxin Yang, Editor(s)

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