Terahertz intensity modulator based on low current controlled vanadium dioxide composite metamaterial

We experimentally demonstrate a terahertz (THz) intensity modulator based on vanadium dioxide (VO2) composite metamaterial. The unit cell of the modulator consists of two toroidal resonators and a central bar on Si3N4-VO2-Si3N4-Si composite substrate. When the current per device area is biased at 3.75 mA/mm(2), the intensity modulation depth reaches 97% and the full width at half maximum (FWHM) is 0.67 THz. Moreover, good linearity and weak hysteresis are observed in experiment. The presented modulator could be very useful for THz communications, imaging and sensing.