Creation of Ro-vibrational Ground State ⁶Li⁴⁰K Molecules

We report on the creation of ground state ⁶Li⁴⁰K molecules with an efficiency of 96%. The singlet stimulated Raman adiabatic passage (STIRAP) pathway is selected to transfer the ultracold ⁶Li⁴⁰K molecules from the Feshbach state to X¹Σ ro-vibrational ground state and |v ′ = 23〉 vibrational state of the unperturbed A¹Σ ⁺ potential is chosen as the intermediate state. After applying a reverse STIRAP pulse, the ground state ⁶Li⁴⁰K molecules are transferred back to the Feshbach state for detection by using absorptive imaging. The single-trip efficiency of 98% can be inferred by comparing the number of molecules before and after the round-trip STIRAP. The lifetime of the ground state molecules is measured to be around 6ms, which is limited by the two-body collision loss. An oscillation at the molecules' ground state has been observed during the lifetime measurement when all-atom species are trapped, and a possible explanation would be discussed.