# Dark resonance formation with magnetically-induced transitions: extension of spectral range and giant circular dichroism

## TL;DR

This paper demonstrates the formation of dark resonances via electromagnetically induced transparency involving magnetically-induced forbidden atomic transitions, extending spectral range and revealing giant circular dichroism in alkali atoms.

## Contribution

It introduces the first observation of dark resonances with magnetically-induced $ riangle F = \pm 2$ transitions, expanding spectral tunability and highlighting anomalous circular dichroism effects.

## Key findings

- Dark resonances formed via magnetically-induced forbidden transitions.
- Resonance tunability in the GHz range with magnetic fields 300-3000 G.
- Observation of giant circular dichroism related to polarization.

## Abstract

Dark resonances were formed via electromagnetically induced transparency for the first time involving magnetically-induced $\Delta F = \pm2$ atomic transitions of alkali metal atom, which are forbidden at zero magnetic field. The probability of these transitions undergoes rapid growth when $300 - 3000$~G magnetic field is applied, allowing formation of dark resonances, widely tunable in the GHz range. It is established that for $\Delta F = +2$ ($\Delta F =-2$) transition, the coupling laser tuned to $\Delta F = +1$ ($\Delta F =-1$) transition of the hyperfine $\Lambda$-system must be $\sigma^+$ ($\sigma^-$) polarized, manifesting anomalous circular dichroism.