Abstract-Gbps Terahertz External Modulator Based on a Composite Metamaterial with a Double-Channel Heterostructure.

Zhang Y1, Qiao S1, Liang S2, Wu Z1, Yang Z1, Feng Z2, Sun H1, Zhou Y1, Sun L1, Chen Z3, Zou X3, Zhang B4, Hu J3, Li S3, Chen Q5, Li L1, Xu G1, Zhao Y1, Liu S1.

• 1†Terahertz Science Cooperative Innovation Center, University of Electronic Science and Technology of China, Chengdu 610054, P. R. China.
• 2‡National Key Laboratory of Application Specific Integrated Circuit, Hebei Semiconductor Research Institute, Shijiazhuang 050000, China.
• 3§National Key Laboratory of Communication, University of Electronic Science and Technology of China, Chengdu 610054, P. R. China.
• 4∥School of Electronics Engineering, University of Electronic Science and Technology of China, Chengdu 610054, P. R. China.
• 5⊥Suzhou Institute of Nano-tech and Nano-bionics, Chinese Academy of Sciences, Suzhou 215123, P. R. China.

http://www.ncbi.nlm.nih.gov/pubmed/25919444

The past few decades have witnessed a substantial increase in terahertz (THz) research. Utilizing THz waves to transmit communication and imaging data has created a high demand for phase and amplitude modulation. However, current active THz devices, including modulators and switches, still cannot meet THz system demands. Double-channel heterostructures, an alternative semiconductor system, can support nanoscale two-dimensional electron gases (2DEGs) with high carrier concentration and mobility and provide a new way to develop active THz devices. In this Letter, we present a composite metamaterial structure that combines an equivalent collective dipolar array with a double-channel heterostructure to obtain an effective, ultrafast, and all-electronic grid-controlled THz modulator. Electrical control allows for resonant mode conversion between two different dipolar resonances in the active device, which significantly improves the modulation speed and depth. This THz modulator is the first to achieve a 1 GHz modulation speed and 85% modulation depth during real-time dynamic tests. Moreover, a 1.19 rad phase shift was realized. A wireless free-space-modulation THz communication system based on this external THz modulator was tested using 0.2 Gbps eye patterns. Therefore, this active composite metamaterial modulator provides a basis for the development of effective and ultrafast dynamic devices for THz wireless communication and imaging systems.