Visualization of Coherent Processes in Plasmonic Interference Transparency

Recently, optical analogs that mimic the dynamics of atomic EIT are attracting attention since they could maintain coherence at room temperature and are easier to fabricate as well as to integrate. However, the understanding of the relationship between atomic EIT and its classical counterparts still remains on the spectroscopic level, which strongly limits the applicability of the analogy. As the coherent evolution of a quantum system is characterized by the oscillatory population transferring between the states, here, we map the coherent oscillation strength of a plamonic interference transparency (PIT) structure and show that there is a deeper resemblance embedded in the analogy: both systems are populated in the `dark' state at the transparency point.