Dipartimento di Fisica

Metamaterials are attracting increasing attention due to their ability to support novel and engineerable functionalities, including exotic electromagnetic and transport properties not available in natural systems.

One of their notable advantages lies in the possibility of manipulating electromagnetic radiation on a sub-wavelength scale, seeking field concentration and improved optical transmission. Consequently, highly localized fields on an engineered interface are useful for the development of nanophotonic sensing devices in different electromagnetic spectral regions.  Recently, our Terahertz and Infrared Photonics group (https://sites.google.com/uniroma1.it/sapienza-terahertz/home) in collaboration with IIT studied a phononic metamaterial composed of Si3N4 membranes patterned with a periodic lattice of micrometric size holes.

We engineered its optical response by demonstrating that the coupling between the incoming electromagnetic wave with an optical Si3N4 phonon triggers an extraordinary optical transmittance (EOT) effect in the technological important infrared spectral region.

The EOT effect was studied by combining state-of-the-art spatially resolved nanoscale infrared measurements with electromagnetic simulations, revealing the formation of a surface phonon polariton excitation that mediates the transmittance enhancement.