Adding trapped molecules to the quantum toolkit
Development of laser-based techniques to cool and manipulate trapped atoms led to a quantum revolution, with applications ranging from creation of novel phases of matter to realization of new tools for navigation and timekeeping. Because of their comparatively richer internal structure, molecules offer additional potential for quantum-controlled chemistry, quantum information processing, and precision spectroscopy. However, obtaining control over the rotational quantum state of trapped molecules, a prerequisite for most applications, has presented a significant challenge because of the large number of internal states. I will discuss techniques we have developed to optically cool rotations of trapped molecular ions, using a single spectrally shaped broadband laser. I will also discuss our progress toward using this quantum control for molecular coherent manipulation, single-molecule fluorescence imaging, and single-molecule spectroscopy.