Lifetime and Emission Characteristics of Electronic Excitations in 2D Optical Lattices

摘要

Collective electronic excitations "excitons" in planar optical latticesexhibit strong modifications of the radiative damping rate and directionalemission pattern as compared to a single excited atom. Excitons for long wavenumbers and polarizations orthogonal to the lattice plane exhibit superradiancewith a very short life time and a tightly confined emission direction. Forshorter wavelength and in plane polarization they can posses a long life time,which beyond a critical wave number tends to infinity. Those excitons thusbecome metastable and decoupled from the free radiation field. They can store asingle energy quantum for a long time and transfer the excitation over longdistances. In general the spatial, polarization and frequency dependence of theemission pattern can provide us with optical and electronic properties ofoptical lattices.