# Efficient optical pumping of alkaline atoms for evanescent fields at dielectric-vapor interfaces

## TL;DR

This paper demonstrates highly efficient hyperfine optical pumping of rubidium atoms at a dielectric-vapor interface using evanescent fields, advancing nanoscale light-atom interaction control for quantum technologies.

## Contribution

It introduces a novel on-chip method for optical pumping at the nanoscale with potential applications in quantum devices.

## Key findings

- Complete suppression of absorption on the evanescent signal.
- Efficient optical pumping achieved with normal incidence pump laser.
- Model based on optical Bloch equations supports experimental results.

## Abstract

We experimentally demonstrate hyperfine optical pumping of rubidium atoms probed by an evanescent electromagnetic field at a dielectric-vapor interface. This light-atom interaction at the nanoscale is investigated using a right angle prism integrated with a vapor cell and excited by evanescent wave under total internal reflection. An efficient hyperfine optical pumping, leading to a complete suppression of absorption on the probed evanescent signal, is observed when a pump laser beam is sent at normal incidence to the interface. In contrast, when the pump and probe beams are co-propagating in the integrated prism-vapor cell, no clear evidence of optical pumping is observed. The experimental results are supported by a detailed model based on optical Bloch equation of a four atomic levels structure. The obtained on-chip highly efficient optical pumping at the nanoscale is regarded as an important step in the quest for applications such as optical switching, magnetometry and quantum memory.

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Source: https://tomesphere.com/paper/1812.08365