1 Materials Research and Education Center, Department of Mechanical Engineering, Auburn University, Auburn, AL, USA.
2 Interdisciplinary Center for Quantum Information, State Key Laboratory of Modern Optical Instrumentation, ZJU-Hangzhou Global Science and Technology Innovation Center, Zhejiang University, Hangzhou, China.
3 Department of Physics, Massachusetts Institute of Technology, Cambridge, MA, USA.
4 Materials Research and Education Center, Department of Mechanical Engineering, Auburn University, Auburn, AL, USA. sdai@auburn.edu.