The resonance fluorescence spectra by choosing different Rabi frequencies: (a) Ω = 0.1; (b) Ω = 10 for N = 0, β = 0 (solid line); N = 0, β = 0.99 (dashed line); N = 0.6, β = 0 (dotted line); N = 0.6, β = 0.99 (dash dotted line). Other parameters are the same as those in Fig. 2.