Fig. 1. Diagram of beam configuration. (a) Energy-level structure; (b) beam configuration

Fig. 2. FWM lines at different Δ1 for g2=g'2=0.3γ10. (a) Δ1/Δ=0.25; (b) Δ1/Δ=0.50; (c) Δ1/Δ=0.75

Fig. 3. FWM lines at different modulation coefficients for g2=g'2=0.3γ10. (a) A=0.5, 0.75, 1; (b) A=3; (c) A=5; (d) A=10

Fig. 4. FWM lines at different dressing field strengths. (a) g2/γ10=0.3, 0.6, 1; (b) g2/γ10=1.2, 1.5, 2, 3

Fig. 5. FWM lines at different modulation coefficients under action of strong dressing field