Enabling an Electrically Tuneable Terahertz Metasurface: graphene gold nanomaterials terahertz CommsMaterials
By Surbhi JainAug 24 2022Reviewed by Susha Cheriyedath, M.Sc. In an article recently published in the journal Communication Materials, researchers discussed the ability of a graphene/gold bilayer construction to enable the electrically tuneable terahertz metasurface.
Two-Dimensional Materials To create electrical and photonic devices operating at terahertz frequencies, novel materials, such as 2D materials like graphene, and device designs including ultrafast charge carrier dynamics and necessary capabilities are highly desired. Electrically tuneable, frequency-selective terahertz absorbers with high Q-factor resonances are highly desired yet difficult to find for constructing terahertz systems.
The team addressed the poor performance of graphene metasurfaces and the lack of tunability of gold metasurfaces by preparing a gold and graphene bilayer metamaterial structure. To prove the effectiveness of the proposed bilayer strategy, a highly tuneable terahertz frequency-selective absorber was created and tested.
Tunable Performance and Broadband Response of the Metamaterial Structure The fitted resonance shifted from 0.192 to 0.187 terahertz and its amplitude increased from about 18 to 25 decibels. With a graphene conductance range of 40 to 100 millisiemens, the simulated peak amplitude shifted from -17 to -22 decibels. These values were very similar to those that were measured experimentally and were -18 decibels at unbiased and -25 decibels at 6 volts bias resonant amplitudes.
The theoretical prediction of the tunability for the bilayer metamaterial design was validated by the experimental findings, which were in good agreement with those of theoretical modeling.