1. Department of Physics and Institute for Soft Matter Synthesis and Metrology, Georgetown University, Washington, D.C.20057, United States
2. Department of Chemistry, Georgetown University, Washington, D.C.20057, United States
3. Department of Physics and Astronomy, Howard University, Washington, D.C.20059, United States
4. Department of Physics, George Mason University, Fairfax, Virginia22030, United States
5. Quantum Science and Engineering Center, George Mason University, Fairfax, Virginia22030, United States