1. Department of Electrical and Computer Engineering, George Washington University, Washington, DC 20052, USA
2. Optelligence LLC, Upper Marlboro, Maryland 20772, USA
3. Fang Lu Mesoscopic Optics and Quantum Electronics Laboratory, University of California, Los Angeles, California 90095, USA
4. Materials Science and Engineering Division, National Institute of Standards and Technology, Gaithersburg, Maryland 20899, USA