Low Voltage Graphene-Based Amplitude Modulator for High Efficiency Terahertz Modulation

Abstract

In this paper, a high-efficiency terahertz amplitude modulation device based on a field-effect transistor has been proposed. The polarization insensitive modulator is designed to achieve a maximum experimental modulation depth of about 53% within 5 V of gate voltages using monolayer graphene. Moreover, the manufacturing processes are inexpensive. Two methods are adopted to improve modulation performance. For one thing, the metal metamaterial designed can effectively enhance the electromagnetic field near single-layer graphene and therefore greatly promote the graphene’s modulation ability in terahertz. For another, polyethylene oxide-based electrolytes (PEO:LiClO4) acts as a high-capacity donor, which makes it possible to dope single-layer graphene at a relatively low voltage.

Flexible Terahertz Metamaterial Biosensor for Ultra-Sensitive Detection of Hepatitis B Viral DNA Based on the Metal-Enhanced Sandwich Assay

“…Secondly, lowpermittivity materials were used to fabricate the substrates of the THz MM biosensor in an effort to minimize induced capacitance and transmission loss. Polyethylene terephthalate (PET) is an ideal flexible MM and a popular electro-optical substrate for various THz biosensor applications due to its low dispersion and loss in the THz range, high optical transparency, good surface smoothness, and simple fabrication of different thicknesses (Chen and Pickwell-MacPherson, 2019;Xia et al, 2019;Hu, et al, 2019;Zheng, et al, 2020;Wang, et al, 2021).…”

Radiation Efficiency Enhancement of Graphene Plasmonic Devices Using Matching Circuits

“…In this framework, various advanced implementations have been proposed until today, such as a wide class of absorbers [13][14][15][16], plasmonic filters [17,18], polarizers [19,20], and modulators [21,22]. Moreover, several fundamental graphene plasmonic antennas have been designed throughout the past years [23][24][25][26][27].…”

Strong Terahertz Absorption of Monolayer Graphene Embedded into a Microcavity

“…However, a monolayer graphene sheet is only one-atom thick, which severely reduces the electromagnetic field-graphene interaction strength. In order to enhance the field-graphene interactions, various structures, for example, graphene-dielectric stacks [ 10 , 11 ], metal-graphene hybrid periodic structures [ 12 , 13 , 14 , 15 , 16 , 17 , 18 , 19 , 20 , 21 ], patterned graphene nanoribbons and patches [ 22 , 23 , 24 , 25 , 26 , 27 ], photonic crystal microcavity integrated with graphene sheet [ 28 , 29 ], and dielectric waveguide covered by graphene layer [ 30 , 31 ], were proposed and fabricated. In these structures, because of the near-field interaction, resonant local electric field enhancement, and the excitation of surface plasmon polaritons (SPPs), strong electromagnetic field-graphene interactions are achieved [ 9 , 32 ].…”

“…Graphene modulators and absorbers based on dielectric waveguides are useful for microwave and terahertz integrated chips; furthermore, such devices can reach higher operation speeds because there are no severe RC time limitations [ 30 , 31 ]. High performance electrically tunable absorbers and modulators can also be realized based on dielectric-graphene structures, for example, multi-graphene-dielectric stacks [ 10 , 11 ], patterned graphene structures [ 22 , 23 , 24 ], and electromagnetic sources integrated with graphene [ 34 ]. To realize high-performance electrically tunable graphene-based modulators with high MD, low insertion loss, and fast operation speed, the following factors must be considered carefully, (i) minimizing the uncontrollable dielectric losses, (ii) strong field-graphene interactions, and (iii) a moderate value of bias voltage.…”