Electromagnetically Induced Transparency and Optical Pumping in the Hyperfine Paschen-Back Regime

TL;DR

This study investigates rubidium vapor under high magnetic fields to explore electromagnetically induced transparency and optical pumping, demonstrating simplified three-level models and potential for improved quantum control in hot vapor systems.

Contribution

It provides detailed spectroscopy of rubidium in the hyperfine Paschen-Back regime, showing how high magnetic fields simplify the atomic structure for quantum control applications.

Findings

Resolved individual optical transitions in high magnetic field

Demonstrated transition from EIT to Autler-Townes splitting

Quantified optical pumping on nuclear spin-forbidden transitions

Abstract

We report spectroscopy experiments of rubidium vapor in a high magnetic field under conditions of electromagnetically induced transparency (EIT) and optical pumping. The 1.1 T static magnetic field decouples nuclear and electronic spins and shifts each magnetic state via the Zeeman effect, allowing us to resolve individual optical transitions of the D$_2$ line in a Doppler-broadened medium. By varying the control laser power driving one leg of a spectrally isolated $\Lambda$ system we tune the vapor from the EIT regime to conditions of Autler-Townes line splitting. The resulting spectra conform to simple three-level models demonstrating the effective simplification of the energetic structure. Further, we quantify the viability of state preparation via optical pumping on nuclear spin-forbidden transitions. We conclude that the ``cleanliness'' of this system greatly enhances the capabilities of quantum control in hot vapor, offering advantages in a broad variety of quantum applications plagued by spurious light-matter interaction processes, such as atomic quantum memories for light.