1. Department of Electrical and Computer Engineering, University of Illinois, Urbana, Illinois 61801, USA
2. Fiber Optics Research and Glass Engineering Laboratory, University of Illinois, Urbana, Illinois 61801, USA
3. Laboratory for Optical Physics and Engineering, University of Illinois, Urbana, Illinois 61801, USA
4. Institut de Chimie Moléculaire et des Matériaux d'Orsay (ICMMO), Université Paris-Saclay, CNRS, 91405 Orsay Cedex, France
5. Department of Materials Science and Engineering, Clemson University, Clemson, South Carolina 29634, USA