1. Environmental Molecular Sciences Laboratory, Pacific Northwest National Laboratory, Richland, Washington 99352, United States
2. 4th Physics Institute, Research Center SCoPE, and Center for Integrated Quantum Optics, IQST University of Stuttgart, Pfaffenwaldring 57, 70569 Stuttgart, Germany
3. Department of Physics, Department of Chemistry, and JILA, University of Colorado at Boulder, Boulder, Colorado 80309, United States