One-laser molecular manipulation

Over the past decade, researchers have refined the art of cooling, trapping and manipulating atoms to perform precision measurements and to use them as quantum bits, or qubits. However, performing the same operations on molecules remains a challenge because their more complicated electronic structure makes them difficult to manipulate. Current methods involve complex procedures with many lasers. But trapped molecules and molecular ions could open exciting possibilities for quantum information processing and precise measurements of fundamental constants. Here the authors establish a general protocol, exploiting a co-trapped atom to help to prepare and coherently manipulate single molecular ions using only one laser. The operations are demonstrated using a CaH⁺ molecular ion, but could be extended to other species. The authors expect that their techniques will enable trapping and manipulation of symmetric molecules such as H₂⁺.