The terahertz (THz) frequency region (0.1-10 THz) is often defined as the last unexplored area of the electromagnetic spectrum. Over the past few years, the full access and exploitation of this frequency window in order to close the so-called “THz gap” have been the objective of intense research efforts both in academia and industry. An increasing number of devices and systems are fabricated, and many applications have been developed in this frequency range. Amongst others, imaging for nondestructive evaluation, chemical and biological sensing, semiconductor characterization, as well as systems for homeland security.

Metamaterials and metasurfaces are artificial materials composed of (3-D and 2-D, respectively) arrangements of sub-wavelength inclusions, which are engineered so as to tailor the effective properties in a precise, desired fashion, not necessarily attainable in conventional materials. They are commonly employed to design novel electro-optical devices with well-defined transmission/reflection signatures, and are therefore ideal candidates to fill the THz gap.

I will present a brief overview on the on-going activities at the University of Naples “Federico II” in the design, fabrication and characterisation using Time Domain Spectroscopy of novel devices for the control of the e.m. signal in the THz range.

Specifically, I will focus on two classes of metamaterials: tunable (hybrid) metadevices for molding the flow of light, and digital (coded) metasurfaces for diffuse scattering.