1. Department of Electrical Engineering, Princeton University, Princeton, New Jersey 08544, United States
2. Laser and Fiber Electronics Group, Faculty of Electronics, Wroclaw University of Science and Technology, Wroclaw 50370, Poland
3. Department of Electrical Engineering and Computer Science, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, United States
4. College of Engineering, University of Notre Dame, Notre Dame, Indiana 46556, United States
5. Center for Integrated Nanotechnology, Sandia National Laboratories, Albuquerque, New Mexico 87123, United States