Narrow inner-shell orbital transition

For the first time, we experimentally observe the transition at 1299nm in atomic erbium. We demonstrate coherent control and perform a detailed study of the transition parameters. Among the large variety of different energy levels available in erbium, the transition at 1299nm is of particular interest due to the associated narrow linewidth. In our experiment, we were able to measure an excited state lifetime of 178(19)ms, which corresponds to a linewidth of 0.9(1)Hz. In particular, we demonstrated the ability to control the atomic population in a coherent manner. In addition, in collaboration with G. Hovhannesyan and M. Lepers from the Laboratoire Interdisciplinaire Carnot de Bourgogne, we present experimental results as well as theoretical calculations on the atomic polarizabilities for the involved atomic states, indicating opportunities for the realization of magic-wavelength or magic-polarizability conditions.

Our work has been published in Physical Review Research.