Figure 1

A schematic depiction for the measured spectra exhibiting anomalous EIA in systems with (a) $F_e=F_g-1$ and (b) $F_e=F_g=1$ (see Figs. 4 and 5 of Ref. 18). The curves show (i) low, (ii) intermediate, and (iii) high coupling field intensity. At low intensity, in both cases an EIA peak is observed within an absorption dip. Increasing the intensity, the EIA peak breaks up in (a) but not in (b). Here $\omega$ is the atomic frequency.Reuse & Permissions

Figure 2

Energy level diagram for systems with $F_e=F_g-1=1$. (a) Bare-atom picture. Solid red arrows and dashed green arrows indicate the coupling and probe excitations, respectively. The solid circles indicate the population distributions without probe field; the atom is trapped in the states $|2⟩$ and $|-2⟩$. (b) Dressed-atom picture. The dotted lines indicate the unperturbed energy levels; solid circles indicate the population distributions without probe field. Encircled numbers label the relevant transitions induced by the probe field. Transitions 1–4 are one-photon bare-to-dressed transitions, 5–8 are two-photon bare-to-dressed transitions. (c) Two-photon excitations between the bare state $|2,n+1⟩$ and the dressed states $|0\pm ,n+2⟩$. Dotted lines indicate the unperturbed energy levels, and solid circles the intermediate states.Reuse & Permissions

Figure 3

(a) Bare-atom level scheme for systems with $F_e=F_g=1$. Solid red arrows and dashed green arrows indicate the coupling and probe excitations, respectively. The transition $|0⟩\to |0^{\prime }⟩$ is forbidden. The solid circle indicates the population distribution without probe field; the population is trapped in $|0⟩$. (b) The corresponding scheme in the dressed-atom picture. The dotted lines indicate the unperturbed energy levels. The arrows indicate the relevant probe field excitations. Channels 1–4 are one-photon bare-to-dressed transitions, while channels 5 and 6 are two-photon bare-to-bare transitions.Reuse & Permissions

Figure 4

Dressed-atom representation for systems with $F_e=F_g=2$. The dotted lines indicate the unperturbed energy levels. The solid circles indicate the population distribution without probe field. The arrows indicate the relevant multiphoton transitions. Channels 1 and 2 are two-photon bare-to-bare transitions, and channels 3–6 are two-photon bare-to-dressed transitions. The one-photon transitions are omitted for clarity.Reuse & Permissions