Fast and Slow Light with Bound States in Continuum

We theoretically demonstrate controllable pulse advancement and delays in a layered medium supporting bound states in continuum (BIC). BIC is achieved via the excitation of the coupled leaky Berreman modes in a symmetric system containing two polar dielectric layers separated by an air gap. We show dramatic enhancement in the delay of the transmitted pulse. While distortion has its toll on the reflected pulse splitting it into two, the transmitted one retains its shape. The time delay can be made comparable with the pulse width.