Gbps THz external modulator based on high electron mobility transistors-metamaterials

Utilizing THz wave to transmit data for communication and imaging places high demands in phase and amplitude modulation. In this paper we combined a metamaterial array with HEMT structure to form an ultrafast electronic grid-controlled THz modulator. By controlling the carrier concentration of 2DEG, a resonant mode conversion between two different dipolar resonances has been realized. In the real-time dynamic test, this THz modulator achieved 1 GHz modulation speed with 85% modulation depth and 1.26 rad phase shift. It could provide an alternate way to achieve effective and ultra-fast active devices in THz wireless communication system.