Magnetic coherent population trapping in a single ion

Magnetically induced coherent population trapping has been studied in a single trapped laser cooled ion. The magnetic-field-dependent narrow spectral feature is found to be a useful tool in determining the null point of magnetic field at the ion position. In particular, we use a double Lambda scheme that allows us to measure the null magnetic-field point limited by the detector shot noise. We analyzed the system theoretically and found certain long-lived bright states as the dark state is generated under steady-state condition.