Dynamic photon-mode selection in Dicke superradiance
C. K. Law, S. K. Y. Lee · Physical Review A · 2007
We examine the mode structures of photons emitted by collective spontaneous decay of ${N}_{A}>1$ excited atoms confined in a small volume. By introducing the notion of dynamical modes, we show how the emission process selects a set of time-dependent mode functions in which photons are optimally occupied. In particular we show that the effective number of such dynamical modes is governed by the separability of the two-time correlation function of atomic dipoles. Due to the nonlinearity of atomic dipoles and quantum fluctuations, more than one mode can be involved even in the large-atom-number limit.