Research Institute of Electrical Communication Tohoku University


Taiichi Otsuji,Professor

Akira Satou,Associate Professor

Takayuki Watanabe,Assistant Professor

(second from the left) T.Otsuji A.Satou T.Watanabe


Research Activities

Terahertz (sub-millimeter) coherent electromagnetic waves are expected to explore the potential application fields of future information and communications technologies. We are developing novel, ultra-broadband integrated signal-processing devices/systems operating in the millimeter and terahertz frequency regime.

Laboratory Web Page

ECEI Web Page

Ultra-Broadband Devices and Systems (Prof. Otsuji)

We are developing novel, integrated electron devices and circuit systems operating in the millimeter-wave and terahertz regions.  III-V- and graphene-based active plasmonic heterostructures for creating new types of terahertz lasers and ultrafast transistors are major concerns. By making full use of these world-leading device/circuit technologies, we are exploring future ultra-broadband wireless communication systems as well as spectroscopic/imaging systems for safety and security.

Research topics

  • Plasmon-resonant terahertz emitters/detectors/modulators and their system applications
  • Graphene-based terahertz lasers and ultrafast transistors, and their system applications

current-injection graphene transistor laser (DFB-DG-GFET). SEM images, measured ambipolar property, simulated modal gain and Q factor, and world-first measured single-mode THz lasing spectra.
world-first observation of terahertz spontaneous emission in double-graphene-layered 2D atomically thin heterojunctions via photoemission-assisted resonant tunneling.
InP-based high electron mobility transistors (HEMT’s) featured by the slant field-plate structure, experimentally confirming its improved high-breakdown voltage performances.