Fig. 1. Energy level diagram of ⁸⁵Rb

Fig. 2. Energy level diagram of ⁸⁷Rb

Fig. 3. Simplified energy level structure of atoms

Fig. 4. Drift velocity of ⁸⁵Rb or ⁸⁷Rb versus excitation laser frequency detuning when I₀=10 W·cm^-2 and Δf=50 MHz

Fig. 5. Atomic population at each energy level of ⁸⁵Rb versus laser frequency detuning when I₀=10 W·cm^-2 and Δf=50 MHz

Fig. 6. Drift velocity versus laser frequency detuning under different ground state hyperfine splitting energy differences when I₀=10 W·cm^-2 and Δf=50 MHz. (a) 1 GHz; (b) 2 GHz; (c) 3 GHz; (d) 4 GHz

Fig. 7. Drift velocity versus laser frequency detuning under different laser power densities when Δf=50 MHz

Fig. 8. Drift velocity versus laser frequency detuning at different laser linewidths when I₀=10 W·cm^-2. (a) 5 MHz; (b) 100 MHz; (c) 1 GHz; (d) 1.5 GHz; (e) 2 GHz; (f) 4 GHz

Fig. 9. Light-induced drift velocity versus laser frequency detuning under different types of lasers when Δf=50 MHz. (a) Single laser, I₀= 10 W·cm^-2; (b) two lasers, I₀= 0.1 W·cm^-2; (c) two lasers, I₀= 1 W·cm^-2; (d) two lasers, I₀= 5 W·cm^-2