Metastability and directional emission characteristics of excitons in 1D optical lattices

Institut für Theoretische Physik, Universität Innsbruck - Technikerstrasse 25, A-6020 Innsbruck, Austria, EU

Corresponding author: hashem.zoubi@uibk.ac.at

Received: 2 February 2010
Accepted: 13 April 2010

Abstract

The radiative damping rate and light emission pattern of electronic excitons in an infinite one-dimensional chain of atoms strongly deviates from independent atom excitations. Exciton emission in the far field is concentrated in cones centered around the chain. Long-wavelength excitons exhibit superradiance with excitation life time orders of magnitude shorter than a single atom. Short-wavelength excitons show reduced spontaneous emission depending on their polarization and beyond a critical wave number they even can get metastable with zero radiation damping rate. Such meta-stable excitations can propagate and mediate interactions over large distances or store photons in the lattice for a long time. While they cannot be directly optically excited, they can be created and read out via tailored evanescent fields from a nearby structured surface or an optical fiber.