Three-photon electromagnetically induced absorption in a dressed atomic system

We present a theoretical treatment for the complete dynamics process of three-photon electromagnetically induced absorption (TPEIA). The nested-cascade doubly dressed TPEIA is considered when two counterpropagating coupling fields are tuned to the upper line in a closed-cycle ladder-type three-level atomic system. The enhancement or suppression of the TPEIA signal relies on the constructive interference between the excitation pathways of doubly dressed states, which can be controlled by changing the intensity of the coupling field. Meanwhile, two symmetrical transparency frequency windows are observed and discussed. The theoretical results and dressed-state analysis are demonstrated experimentally in the 5 S 1 / 2 ( F = 2 ) − 5 P 3 / 2 ( F ′ = 3 ) − 5 D 5 / 2 ( F ′ ′ = 4 ) transition of the 87 R b atoms.