High-quality factor resonance enabled by the weak coupling between TE and TM resonance modes in a two-dimensional asymmetric metasurface and its application for slow light

In this work, the interaction between a transverse electric (TE) resonance mode and a transverse magnetic (TM) resonance mode in an asymmetric two-dimensional metal-dielectric guided mode resonance metasurface structure is investigated by using finite-difference time-domain simulations and a two-oscillator coupled mode theory. The coupled oscillator model fits well with the numerical simulation results. A Fano-like resonance mode attributed to the weak coupling between the TE and TM resonance modes is discovered in the resonance metasurface structure. The weakly coupled resonance mode has a high-quality factor of 14935, which is 33 times the quality factor of the uncoupled TE resonance mode. The high-quality factor resonance can be utilized to generate slow light. A group delay of 0.46 picosecond has been obtained in one designed asymmetric resonance metasurface.