We use electromagnetically induced transparency (EIT) laser cooling to cool motional modes of a linear ion chain. As a demonstration, we apply EIT cooling on 24Mg+ ions to cool the axial modes of a 9Be+ - 24Mg+ ion pair and a 9Be+ - 24Mg+ - 24Mg+ - 9Be+ ion chain, thereby sympathetically cooling the 9Be+ ions. Compared to previous implementations of conventional Raman sideband cooling, we achieve approximately an order-of-magnitude reduction in the duration required to cool the modes to near the ground state and significant reduction in required laser intensity.
@article{arxiv.1211.6647,
title = {Sympathetic EIT laser cooling of motional modes in an ion chain},
author = {Y. Lin and J. P. Gaebler and T. R. Tan and R. Bowler and J. D. Jost and D. Leibfried and D. J. Wineland},
journal= {arXiv preprint arXiv:1211.6647},
year = {2014}
}