A graphene-metal metasurface for terahertz modulation with a depth of several orders of magnitude

Next-generation communication systems require rapid and efficient control of terahertz (THz) signals to encode data streams. Graphene-based metamaterials emerge as a promising candidate for effective THz modulation as a result of graphene’s large electrically controllable conductivity. However, a significant challenge arises from the inability of graphene to achieve full depletion at the Dirac point, limiting the modulation depth in most LC-resonant metamaterial modulators in transmission. To overcome this limitation, we exploit the destructive interference of Fresnel reflection components. Our study shows single-layer, solid-state graphene-based modulators operating in the terahertz range with several orders of magnitude modulation depth, validated through terahertz time-domain spectroscopy measurements. These findings underscore the potential of graphene-based metamaterials in advancing THz communication technologies.