High resolution electromagnetically induced transparency spectroscopy of Rydberg 87Rb atom in a magnetic field

We have studied the high resolution spectroscopy of Rydberg state Rb-87 in a ladder-type electromagnetically induced transparency (EIT) configuration at room temperature. A highly excited Rydberg atom is nearly degenerate for its hyperfine states but this degeneracy will be broken by an applied magnetic field, resulting in a spectral splitting in a coupled basis. In our ladder-type EIT experiment, we observed the high resolution spectral splitting of Rydberg atoms in an external magnetic field with two different optical polarization combinations of sigma(+) - sigma(+) and sigma(+) - sigma(+) for probe and coupling laser beams. A strict theory has been set up to explain the observed spectral line position and intensity accurately considering the Zeeman effects of three EIT-concerned states all in the coupled basis. Specially for the Rydberg state, we can transform its wavefunction back into the decoupled basis for the spectral line assignment. (C) 2017 Optical Society of America under the terms of the OSA Open Access Publishing Agreement