Figure 5
Effective quantum state reconstruction from the emission of a two-level system under high (a) incoherent and (b) coherent excitation. The various blue areas correspond to different filters linewidths. The light filtered in this way is equivalent to an unfiltered emitter whose quantum state has distribution p(n) to have n excitations, and is shown in (b) and (d), respectively. For the incoherently driven two-level system, case (a), the system is kept in its excited state by large pumping, so that without filtering, one observes a state close to the Fock state p(n) = δn,1. Filtering leads to thermalization, with preponderance of vacuum but nonzero probability to detect \(n > 1\) particles. The same is observed for the coherently driven two-level system, case (b), but starting from p(0) = p(1) = 1/2 due to the no-inversion of a two-level system in presence of stimulated emission. Parameters: for incoherent excitation, P σ = 102γ σ (saturating the two-level system). For coherent excitation, Ω = 5γ σ . The rest of the parameters are as indicated in the figure.
