Dark-state cooling of a trapped ion using microwave coupling.

We propose a dark-state cooling method of trapped ion systems in the Lamb-Dicke limit. By microwave dressing the ion, we can obtain two electromagnetically induced transparency structures. The heating effects caused by the carrier and the blue sideband transition vanish due to electromagnetically induced transparency effects and the final mean phonon numbers can be much lower than the recoil limit. Our scheme is robust to fluctuations of microwave power and laser intensities, which provides a broad cooling bandwidth to cool motional modes of a linear ion chain. Moreover, it is more suitable to cool four-level ions on a large-scale ion chip. [ABSTRACT FROM AUTHOR]