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Graphene Based Terahertz Light Modulator in Total Internal Reflection Geometry
Author(s) -
Liu Xudong,
Chen Zefeng,
Parrott Edward P. J.,
Ung Benjamin S.Y.,
Xu Jianbin,
PickwellMacPherson Emma
Publication year - 2017
Publication title -
advanced optical materials
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.89
H-Index - 91
ISSN - 2195-1071
DOI - 10.1002/adom.201600697
Subject(s) - terahertz radiation , materials science , modulation (music) , graphene , total internal reflection , metamaterial , optoelectronics , optics , reflection (computer programming) , fresnel equations , amplitude modulation , broadband , frequency modulation , nanotechnology , computer science , telecommunications , refractive index , physics , acoustics , bandwidth (computing) , programming language
Modulation of visible light has been easily achieved for decades, but modulation of terahertz (THz) light still remains a challenge. To address this issue, the Fresnel equations have been developed to describe a conductive interface in a total internal reflection geometry and reveal a new approach for modulation. To demonstrate this new mechanism, a broadband device achieving a modulation depth greater than 90% between 0.15 and 0.4 THz, and reaching a maximum of 99.3% at 0.24 THz has been designed. The modulation is achieved by applying a gate voltage between −0.1 and 2 V to a graphene layer in a total internal reflection geometry. Compared to conventional designs, the high modulation is realized without assistance from metamaterial structures, resonant cavities, or multistacked graphene layers. Thus, the design is efficient and easy‐to‐fabricate and can be easily retrofitted to most existing THz systems. This work opens up a new avenue of research as the device has verified the theory and demonstrates how it can be used to make practical devices, bringing a promising new paradigm for THz modulation, thin‐film sensing, and noninvasive material characterization.