Electrically tuneable terahertz metasurface enabled by a graphene/gold bilayer structure

Reconfigurable terahertz electronics devices with high tuneability are pivotal for next-generation high speed wireless communication and sensing technologies. Significant challenges exist for realizing these devices, particularly on the design of smart metastructures that can manipulate electromagnetic radiation at the terahertz frequencies and the fabrication of devices with effective tuneability and reconfigurability. Here, we incorporate graphene into a graphene/gold bilayer superimposed metamaterial structure, which enables efficient electrical tuning of terahertz waves. A 0.2 THz frequency-selective absorber is designed and experimentally developed using this graphene/gold bilayer metamaterial approach. The device demonstrates 16 dB amplitude tuning at 0.2 THz resonance and over 95% broadband modulation at just 6 V bias voltage while maintaining a benchmark high-quality factor resonance performance. The design and fabrication methods presented can be readily applied to produce a myriad of tuneable terahertz devices required for high-speed, reconfigurable THz wireless communication and sensing technologies. Reconfigurable and tunable terahertz electronic devices are promising for various technological applications, for which metamaterials are receiving interest. Here, a graphene/gold bilayer metasurface enables the creation of a frequency-selective absorber with electrical tuning in the 0.1–1 THz range.