Sun, Yiwen and Degl'Innocenti, Riccardo and Ritchie, David and Beere, Harvey and Xiao, Long and Ruggiero, Michael and Zeitler, J. Axel and Stantchev, Rayko and Chen, Danny and Peng, Zhengchun and MacPherson, Emma and Liu, Xudong (2018) Graphene-loaded metal wire grating for deep and broadband THz modulation in total internal reflection geometry. Photonics Research, 6 (12). pp. 1151-1157. ISSN 2327-9125
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Abstract
We employed a metallic wire grating loaded with graphene and operating in total internal reflection (TIR) geometry to realize deep and broadband THz modulation. The non-resonant field enhancement effect of the evanescent wave in TIR geometry and in the subwavelength wire grating was combined to demonstrate a∼ 77% modulation depth (MD) in the frequency range of 0.2 –1.4 THz. This MD, achieved electrically with a SiO2∕Si gated graphene device, was 4.5 times higher than that of the device without a metal grating in transmission geometry. By optimizing the parameters of the metallic wire grating, the required sheet conductivity of graphene for deep modulation was lowered to 0.87 mS. This work has potential applications in THz communication and real-time THz imaging