$\mathcal{P},\mathcal{T}$-odd Faraday effect in intracavity absorption spectroscopy

It is proposed to observe the $\mathcal{P},\mathcal{T}$-odd Faraday effect, i.e., the rotation of the polarization plane of the light propagating through a medium in the presence of an electric field in intracavity absorption spectroscopy experiments. The $\mathcal{P},\mathcal{T}$-odd Faraday effect may be caused by $\mathcal{C}\mathcal{P}$ violation within the standard model. For this purpose the vapors of heavy atoms such as Tl, Pb, and Bi are most suitable. Estimates based on the achievements of modern intracavity absorption spectroscopy demonstrate that the observation of the $\mathcal{P},\mathcal{T}$-odd Faraday effect may compete with the observation of the $\mathcal{P},\mathcal{T}$-odd electron spin rotation in an external electric field which now provides the most stringent bounds for the $\mathcal{P},\mathcal{T}$-odd effects in atomic physics.

Figure 1

Behavior of the functions $g\left(u\right), f\left(u\right)$, and $h\left(u\right)$ close to resonance. (a) The behavior of the rotation angle for optical rotation (natural or $\mathcal{P}$-odd) (b) $L_0^{-1}$, where $L_0$ is the absorption length, and (c) the rotation angle for the Faraday effect (ordinary or $\mathcal{P},\mathcal{T}$ odd).