Saturation Spectroscopy of Iodine in Hollow-core Optical Fibre

TL;DR

This paper demonstrates high-resolution iodine spectroscopy within a hollow-core photonic crystal fibre, achieving sub-Doppler features and providing a theoretical model that matches experimental results.

Contribution

It introduces a novel method for iodine spectroscopy in a hollow-core fibre, showing sub-Doppler resolution and a simple theoretical explanation.

Findings

Sub-Doppler spectral features with ~6 MHz width achieved

Significant differences in saturation characteristics compared to conventional cells

Theoretical model closely matches experimental observations

Abstract

We present high-resolution spectroscopy of Iodine vapour that is loaded and trapped within the core of a hollow-core photonic crystal fibre (HC-PCF). We compare the observed spectroscopic features to those seen in a conventional iodine cell and show that the saturation characteristics differ significantly. Despite the confined geometry it was still possible to obtain sub-Doppler features with a spectral width of ~6 MHz with very high contrast. We provide a simple theory which closely reproduces all the key observations of the experiment.