Toward Quantum Logic Spectroscopy of Molecular Ions

Quantum logic spectroscopy (QLS) demands reliable state preparation of the subject's external and internal quantum numbers, a challenging task for molecules owing to their numerous internal degrees of freedom. Having recently achieved rapid rotational ground state cooling with the aluminum monohydride cation (AlH$^{+}$)\footnote{C.-Y. Lien, C.S. Seck, Y.-W. Lin, J.H.V. Nguyen, D.A. Tabor, and B.C. Odom. Nat. Commun. \textbf{5}, 4783 (2014).}, we now present progress toward demonstrating QLS with AlH$^{+}$. We have implemented a new, efficient source for AlH$^{+}$ production via resonance enhanced multiphoton ionization (REMPI) of neutral aluminum monohydride (AlH). AlH is formed by ablation of aluminum in the presence of hydrogen gas. Following production, we then prepare the AlH$^{+}$ ions in a well-defined internal state. In addition, we demonstrate progress toward ground state cooling AlH$^{+}$ through sympathetic cooling with atomic barium ions (Ba$^{+}$). Ba$^{+}$ will then serve as our readout qubit in QLS.