Doppler cooling of calcium ions using a dipole-forbidden transition

TL;DR

This paper demonstrates Doppler cooling of calcium ions via a dipole-forbidden transition, achieving lower scattering forces and enabling nearly background-free single-ion detection, which benefits quantum information processing.

Contribution

It introduces a novel Doppler cooling method using a dipole-forbidden transition, enhancing detection capabilities for ion trap quantum computing.

Findings

Scattering forces are five times smaller than traditional methods.

Single ions can be detected with near-zero background.

The cooling scheme is advantageous for quantum information applications.

Abstract

Doppler cooling of calcium ions has been experimentally demonstrated using the S1/2 to D5/2 dipole-forbidden transition. Scattering forces and fluorescence levels a factor of 5 smaller than for usual Doppler cooling on the dipole allowed S1/2 to P1/2 transition have been achieved. Since the light scattered from the ions can be monitored at (violet) wavelengths that are very different from the excitation wavelengths, single ions can be detected with an essentially zero background level. This, as well as other features of the cooling scheme, can be extremely valuable for ion trap based quantum information processing.