Fig. 5: Spectral dependence of the purification effect.
From: Large scale purification in semiconductors using Rydberg excitons
a The linear absorption spectrum from Fig. 1a in the energy range from n = 8 to the band gap, shown as a reference. The red dashed line indicates the background that is dominated by an exponential tail below the apparent band gap \({\tilde{E}}_{g}\). b Probe laser absorption coefficient as a function of pump laser energy. The probe laser energy is fixed to the peak of the nprobe = 12 exciton resonance, while the pump laser energy is scanned. The pump laser enhances the absorption of nprobe = 12 if its energy is set within a spectral range around the apparent band gap \({\tilde{E}}_{{{{{{{{\rm{g}}}}}}}}}\). The grey dashed vertical line marks the resonance energy of n = 12, the grey dashed horizontal line marks the absorption coefficient of n = 12 without the presence of a pump laser α12,0. Panel (c) shows an extended energy range of panel (b).
