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.

Table 1. Number of Resonant Frequency Modes in MWM Process

Table 2. Number of Central Spatial Modes for Each Signal in MWM Process