Improving cavity lifetime by electromagnetic-induced-transparency-like meta-atoms

In this paper, lifetime enhancement in a microstrip photonic crystal (PC) cavity by embedding electromagnetic-induced-transparency (EIT)-like meta-atoms is reported. Both microwave experiments and numerical simulations confirm that cavity lifetime can be lengthened about four times, with enhanced Q-factor simultaneously. Further study on electromagnetic field distribution reveals that these enhancements are mainly originated from the confinement along the propagating direction provided by PC cavity and the in-unit localization from the EIT-like meta-atoms. Moreover, study on the group delay shows that by introducing multiple EIT-like meta-atoms, these improvements of cavity lifetime and Q-factor can even be superimposed. As these advantages are not at a cost of extra device volume, the design principle of composite PC–EIT structure is promising to be applied in nonlinear optical devices, optical storage, lasing optics, and so on.