Breakdown of Angular Momentum Selection Rules in High Pressure Optical Pumping Experiments

TL;DR

This paper investigates how high-pressure conditions cause the breakdown of angular momentum selection rules in atomic systems, affecting optical pumping efficiency due to collision-induced mixing.

Contribution

It provides experimental evidence of selection rule breakdown in He-broadened Rb vapor caused by fine-structure mixing during collisions.

Findings

Atomic dark states become weakly absorbing due to collisions.

Selection rules break down under high-pressure conditions.

Photon demand for optical pumping increases significantly.

Abstract

We present measurements, using two complementary methods, of the breakdown of atomic angular momentum selection rules in He-broadened Rb vapor. Atomic dark states are rendered weakly absorbing due to fine-structure mixing during Rb-He collisions. The effect substantially increases the photon demand for optical pumping of dense vapors.