1. Department of Electrical & Computer Engineering, The University of Texas at Austin, Austin, Texas 78712, United States
2. Department of Physics, The University of Texas at Austin, Austin, Texas 78712, United States
3. Department of Electrical and Computer Engineering, National University of Singapore, Kent Ridge, Singapore 117583, Republic of Singapore
4. Photonics Initiative, Advanced Science Research Center, City University of New York, New York 10031, United States
5. Department of Mechanical Engineering, The University of Texas at Austin, Austin, Texas 78712, United States
6. Physics Program, Graduate Center, City University of New York, New York 10016, United States
7. Department of Electrical Engineering, City College of The City University of New York, New York 10031, United States