1. Smart State Center for Experimental Nanoscale Physics Department of Physics and Astronomy University of South Carolina Columbia SC 29208 USA
2. Department of Electrical and Computer Engineering University of Texas at Austin Austin TX 78712 USA
3. Naval Research Laboratory Washington D.C. 20375‐5347 USA
4. Photonics Initiative Advanced Science Research Center City University of New York New York NY 10031 USA
5. Physics Program Graduate Center of the City University of New York New York NY 10016 USA
6. Department of Electrical Engineering City College of New York New York NY 10031 USA