Velocity-selective spectroscopy measurements of Rydberg fine structure states in a hot vapor cell

He Jun^{1, 2, 3}, Pei Dongliang¹, Wang Jieying¹, Wang Junmin^{1, 2, 3, †}

(color online) Energy level schematic of the cascade-type electromagnetically induced transparency (EIT) of ¹³³Cs. The λ_p = 852 nm probe laser is frequency-stabilized to the hyperfine transition to measure the absorption on the 6S_1/2 (F = 4) → 6P_3/2 (F′ = 5) transition, while the λ_c = 509 nm laser beam is coupled to the 6P → nS(D) transition.