Description
Resonance plot for a cascade three-level atomic system, showing the Autler–Townes doublet and electromagnetically induced transparency (EIT). The level structure with Stark shifts is displayed when at least one of the fields is weak, since the level splitting becomes very complex when both fields are strong.
Physical model
The graph is obtained from the algebraic steady-state solution of the Bloch equations [1]. The Stark shifts of the levels from their original positions are given by [2]
$$
\omega_{\pm} = \dfrac{\delta - kv}{2} \pm \dfrac{1}{2} \sqrt{ 4\Omega^2 + (\delta-kv)^2},
$$
where $\delta$, $\Omega$, and $k$ are the detuning, Rabi frequency, and wavenumber of the strong field, and $v$ is the component of the atom's velocity along the strong-field direction.
Controls
Adjust the Rabi frequencies and detunings of the two fields, the atomic-system velocity/wavelengths, and the decay rates in the parameter panels. "Swept detuning" selects which detuning (δ12 or δ23) is swept along the graph's horizontal axis; "Configuration" selects whether the two fields are co- or counterpropagating. The "Graph" panel shows ρ33 as a function of the selected detuning; the adjacent level diagram is displayed only when at least one field is weak (Ω/2π < 1 MHz).
Developers
Marco P. M. de Souza
References
[2] Y. R. Shen, The Principles of Nonlinear Optics (Wiley-Interscience, first edition, 2002).
[3] Christopher J. Foot, Atomic Physics (Oxford University Press, first edition, 2005).