Extremely subradiant states in a periodic one-dimensional atomic array
Danil Kornovan, Neil Corzo, Julien Laurat, A. S. Sheremet · Physical Review A · 2019
We study the subradiant collective states of a periodic chain of two-level atoms with either transversal or longitudinal transition dipole moments with respect to the chain axis. We show that long-lived subradiant states can be obtained for the transversal polarization by properly choosing the chain period for a given number of atoms in the case of no open diffraction channels. While not being robust against the positional disorder along the chain, these highly subradiant states have a linewidth that decreases with the number of atoms much faster than it was shown previously. In addition, our paper shows that similar states are present even if there are additional interaction channels between the atoms, i.e., they interact via the waveguide mode of an optical nanofiber, for instance. We develop a theoretical framework allowing us to describe the spectral properties of the system in terms of contributions from each collective eigenstate and we show that subradiant states manifest themselves in the transmission and reflection spectra, allowing us to observe interaction-induced transparency in a very narrow spectral range. Such long-lived collective states may find potential applications in nanophotonics and quantum optics.