Graphene Based Terahertz Light Modulator in Total Internal Reflection Geometry

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 f...

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Bibliographic Details
Published in:Advanced optical materials 2017-02, Vol.5 (3), p.np-n/a
Main Authors: Liu, Xudong, Chen, Zefeng, Parrott, Edward P. J., Ung, Benjamin S.‐Y., Xu, Jianbin, Pickwell‐MacPherson, Emma
Format: Article
Language:English
Subjects:
Design
Design engineering
Detection
Devices
electrical control
Geometry
Graphene
light modulation
Mathematical analysis
Modulation
Optics
Reflection
terahertz
Thin films
total internal reflection
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Summary: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. Here, a new modulation approach and physical device with a high modulation depth (up to 99.3%) across 0.1–0.7 THz is presented. The device demonstrates that the new theory can be applied to make practical devices, bringing a promising new paradigm for terahertz modulation, thin‐film sensing, and noninvasive material characterization.
ISSN:2195-1071
2195-1071
DOI:10.1002/adom.201600697