Control and manipulation of cold molecular ions

Due to rich level structure, long trapping time and good isolation from environment, molecular ions confined in an rf-Paul trap are attractive for precision measurements and quantum information processing. Translational degrees of freedom of the molecular ion can be sympathetically cooled by laser-cooled atomic ions confined in the same trap. However control of an internal molecular state remains a challenging problem. A frequency comb generated by a mode-locked pulsed laser offers a tool to address ro-vibrational states of molecules via simulated Raman transitions. Based on quantum logic techniques we present a scheme for preparation, manipulation, and detection of internal states of molecular ions and report progress towards its experimental implementation.