Exponential improvement in photon storage fidelities using subradiance and “selective radiance” in atomic arrays
In quantum optics, strong light-matter interactions are typically thwarted by loss. Spontaneous emission, in which photons are absorbed by atoms and then re-scattered into undesired channels, fundamentally limits how strongly atoms interact with preferred photonic modes. Typically, it is assumed that this re-scattering occurs independently, and at a rate given by a single isolated atom. We find that this assumption does not hold when atoms are close enough to each other so that they give rise to collective subradiant states, whose free-space decay is significantly suppressed. Inspired by subradiance, we introduce the new concept of “selective radiance”. Whereas subradiant states experience a reduced coupling to all optical modes, selectively radiant states are tailored to simultaneously radiate efficiently into a desired channel while scattering into undesired channels is suppressed, thus enabling an enhanced atom-light interface. We show that these states naturally appear in chains of atoms coupled to nanophotonic structures. We find that selectively radiant states allow for a photon storage fidelity that performs exponentially better with number of atoms than previously known bounds.
Host: Luis A. Orozco