Lamb-Dicke spectroscopy of atoms in a hollow-core photonic crystal fibre

TL;DR

This paper introduces a new method for precision spectroscopy using ultracold atoms confined in a hollow-core photonic crystal fibre, reducing decoherence and enabling high-resolution measurements.

Contribution

It demonstrates trapping single atoms in a magic lattice inside a hollow-core fibre, achieving narrow spectral lines and improved coherence for atomic spectroscopy.

Findings

Observed a 7.8-kHz-wide spectrum for the $^1 S_0-{}^3P_1$ transition

Confined atoms in a magic lattice to enhance coherence time

Reduced atom-wall interactions to improve atomic clock performance

Abstract

Unlike photons, which are conveniently handled by mirrors and optical fibres without loss of coherence, atoms lose their coherence via atom-atom and atom-wall interactions. This decoherence of atoms deteriorates the performance of atomic clocks and magnetometers, and also hinders their miniaturisation. Here we report a novel platform for precision spectroscopy. Ultracold strontium atoms inside a kKagome-lattice hollow-core photonic crystal fibre (HC-PCF) are transversely confined by an optical lattice to prevent atoms from interacting with the fibre wall. By confining at most one atom in each lattice site, to avoid atom-atom interactions and Doppler effect, a 7.8-kHz-wide spectrum is observed for the $^1 S_0-{}^3P_1$ (m=0) transition. Atoms singly trapped in a magic lattice in hollow-core photonic crystal fibresHC-PCFs improve the optical depth while preserving atomic coherence time.