1. School of Electrical and Computer Engineering, Georgia Institute of Technology, 778 Atlantic Drive NW, Atlanta, Georgia 30332-0250, United States
2. Department of Electrical Engineering, Department of Materials Science and Engineering, Precourt Institute for Energy, Stanford University, Stanford, California 94305, United States
3. School of Materials Science and Engineering, Georgia Institute of Technology, 801 Ferst Drive NW, Atlanta, Georgia 30332-0295, United States
4. Laser Dynamics Laboratory, School of Chemistry and Biochemistry, Georgia Institute of Technology, Atlanta, Georgia 30332-0400, United States