Direct Observation of THz Bound States in the Continuum

Bound states in the Continuum (BICs) represent a new paradigm for resonant photonics due to their infinite lifetime associated with the full suppression of radiation losses. This property makes it also impossible to directly measure BICs with standard far-field spectroscopic techniques. Here, we directly observe the temporal evolution of a BIC by using a near-field excitation and detection microscope.