Fig. 1. (a) Experimental setup. PBS, polarized beam splitter; BS, beam splitter; M, mirror; APD, avalanche photodiode. (b) Energy diagram; (c) phase-mismatching diagram; (d) emission cone of Stokes.

Fig. 2. Third-order nonlinear susceptibility of Stokes and anti-Stokes signals versus frequency linewidth δ obtained from FWM; (a1), (a2) without dressing effect; (b1), (b2) with E3 field single-dressing effect; (c1), (c2) with E3 and E4 double-dressing effect; (d1), (d2) fifth-order nonlinear susceptibility versus frequency linewidth δ obtained in SWM, δ1+δ2+δ3=0.

Fig. 3. (a1) In FWM process, the emission cone of Stokes signal; (a2) parametric amplified Stokes signal. The cross section of Stokes and anti-Stokes signals in FWM: (b1), (b2) without E3 laser dressing; (c1), (c2) with E3 laser dressing; (d1), (d2) with E3 and E4 lasers’ double dressing.

Fig. 4. (a1)–(a3) Cross sections of S1, S2, and S3 signals cone in SWM with E3 and E4 lasers’ dressing; (b1)–(b3) partial enlargements of (a1), (a2), and (a3), respectively.

Fig. 5. In PA-FWM process, evolutions of the generated anti-Stokes signals’ spatial images captured by discretely modifying pumping frequency detuning Δ1. (a1)–(a6) Rb temperature is 55°C; (b1)–(b6) Rb temperature is 70°C; (c1)–(c6) Rb temperature is 85°C; (d1) frequency spectrum of anti-Stokes versus pumping frequency detuning Δ1 at different diameters D of pump beam E1; (d2) frequency spectrum of anti-Stokes versus external dressing laser E3 frequency detuning Δ3 at discrete Δ1.

Fig. 6. In PA-SWM process, evolutions of the generated S1 signal spatial image captured by discretely modifying pumping frequency detuning Δ1. (a1)–(a6) Rb temperature is set to 60°C; (b1)–(b6) Rb temperature is set to 80°C; (c1)–(c6) Rb temperature is set to 100°C; (d1) frequency spectrum of anti-Stokes versus pumping frequency detuning Δ1 at discrete E4 frequency detuning; (d2) frequency spectrum of anti-Stokes versus laser E3 frequency detuning Δ3 at discrete E4 frequency detuning.