Fig. 2

Real (dashed) and imaginary (solid) parts of susceptibility as a probe field wavelength for (a). T ₁₂ = 0, THz signal = of, Λ = 0, (b) T ₁₂ = 1 γ, THz signal = of, Λ = 0, (c) T ₁₂ = 1 γ, ,THz signal = on,Λ = 0, Other parameters are ω ₁₂ = ω ₂₃ = 1γ, Γ ₀₁ = γ = 1 THz, Γ ₀₂ = 0.1 Γ ₀₁, Γ ₀₃ = 0.01 Γ ₀₁, Γ ₁₂ = 0.05 Γ ₀₁, Γ ₁₃ = 0.025 Γ ₀₁, Γ ₂₃ = 0.05 Γ ₀₁, γ ₁₀ = 0.6 THz, γ ₂₀ = 0.1 γ ₁₀, γ ₃₀ = 0.01 γ ₁₀ Ω _p  = 0.01 γ