Unveiling the Symmetry Protection of Bound States in the Continuum with Terahertz Near-Field Imaging.

ABSTRACT: Bound states in the continuum (BICs) represent a new paradigm in photonics due to the full suppression of radiation losses. However, this suppression has also hampered the direct observation of them. By using a double terahertz (THz) near-field technique that allows the local excitation and detection of the THz amplitude, we are able to map for the first time the electromagnetic field amplitude and phase of BICs over extended areas, unveiling the field-symmetry protection that suppresses the far-field radiation. This investigation, done for metasurfaces of dimer scatterers, reveals the in-plane extension and formation of BICs with antisymmetric phases, in agreement with coupled-dipole calculations. By displacing the scatterers, we show experimentally that a mirror symmetry is not a necessa

SUBMITTER: van Hoof NJJ 

PROVIDER: S-EPMC8532159 | biostudies-literature | 2021 Oct

REPOSITORIES: biostudies-literature