Steady-state linear optical properties and Kerr nonlinear optical response of a four-level quantum dot with phonon-assisted transition

She Yan-Chao^{1, 2, †,}, Luo Ting-Ting², Zhang Wei-Xi¹, Ran Mao-Wu¹, Wang Deng-Long^{2, ‡,}

Variations of group velocity reduction factor of the probe field versus the PAT coefficientκfor different values of Rabi energies of the control fieldsΩ_aandΩ_b: (a)Ω_a= 2.0 meV andΩ_b= 1.5 meV, (b)Ω_a= 1.0 meV andΩ_b= 1.5 meV, (c)Ω_a=Ω_b= 1.5 meV, (d)Ω_a=Ω_b= 1.0 meV. Other parameters used are the same as those in Fig. 2.