Lifetime and emission characteristics of collective electronic excitations in two-dimensionaloptical lattices

摘要

Collective electronic excitations in planar optical lattices exhibit strong modifications of the radiative dampingrate and directional emission pattern as compared to a single excited atom. Collective excitations for long wavenumbers and polarizations orthogonal to the lattice plane exhibit superradiance with a very short lifetime and atightly confined emission direction. For shorter wavelength and in-plane polarization, they can possess a longlifetime, which, beyond a critical wave number, tends to infinity. Those excitations thus become metastable anddecoupled from the free radiation field. They can store a single energy quantum for a long time and transfer theexcitation over long distances. In general the spatial, polarization, and frequency dependence of the emissionpattern can provide us with optical and electronic properties of optical lattices.