# Alignment-dependent decay rate of an atomic dipole near an optical nanofiber

## TL;DR

This paper investigates how the spontaneous emission rate of rubidium atoms is modified by their proximity to an optical nanofiber, revealing alignment-dependent enhancement and inhibition effects crucial for quantum photonics.

## Contribution

It demonstrates the alignment-dependent decay rate modification near nanofibers and shows that simple dipole models match experiments despite atomic complexity.

## Key findings

- Decay rate can be enhanced or inhibited depending on dipole alignment.
- Finite-difference time-domain simulations agree with measurements.
- Multi-level atomic structure effects are less significant than expected.

## Abstract

We study the modification of the atomic spontaneous emission rate, i.e. Purcell effect, of $^{87}$Rb in the vicinity of an optical nanofiber ($\sim$500 nm diameter). We observe enhancement and inhibition of the atomic decay rate depending on the alignment of the induced atomic dipole relative to the nanofiber. Finite-difference time-domain simulations are in quantitative agreement with the measurements when considering the atoms as simple oscillating linear dipoles. This is surprising since the multi-level nature of the atoms should produce a different radiation pattern, predicting smaller modification of the lifetime than the measured ones. This work is a step towards characterizing and controlling atomic properties near optical waveguides, fundamental tools for the development of quantum photonics.