CUED Publications database

Fast terahertz optoelectronic amplitude modulator based on plasmonic metamaterial antenna arrays and graphene

Jessop, DS and Sol, CWO and Xiao, L and Kindness, SJ and Braeuninger-Weimer, P and Lin, H and Griffiths, JP and Ren, Y and Kamboj, VS and Hofmann, S and Axel Zeitler, J and Beere, HE and Ritchie, DA and Degl'Innocenti, R (2016) Fast terahertz optoelectronic amplitude modulator based on plasmonic metamaterial antenna arrays and graphene. In: UNSPECIFIED.

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© 2016 SPIE. 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.

Item Type: Conference or Workshop Item (UNSPECIFIED)
Divisions: Div B > Solid State Electronics and Nanoscale Science
Div B > Photonics
Depositing User: Cron Job
Date Deposited: 17 Jul 2017 19:00
Last Modified: 24 May 2018 01:57