Large-scale terahertz active arrays in silicon using highly-versatile electromagnetic structures

The high integration capability of silicon technologies, as well as the small wavelength of terahertz (THz) signals, make it possible to build a high-density, very-large-scale active THz array on a single chip. This is, however, very challenging in practice, due to the low device efficiency and large footprint of conventional circuit designs. To address these problems, we introduce a set of compact while versatile circuits, which utilize the multi-mode behaviors from structures with tight device-electromagnetic integration. These circuits have enabled large-scale (1) homogeneous arrays for high-power, collimated radiation, and (2) heterogeneous arrays for fast broadband spectral scanning. In particular, 0.1-mW power generation (20-mW effective isotropically-radiated power) at 1 THz, simultaneous transmit/receive capability, and high-parallelism molecular spectroscopy are demonstrated. New opportunities that these works bring about are also discussed.