1. Microelectronics-Photonics Graduate Program, University of Arkansas, Fayetteville, Arkansas 72701, United States
2. R.B. Annis School of Engineering, University of Indianapolis, Indianapolis, Indiana 46227, United States
3. Department of Electrical and Computer Engineering, University of Nebraska-Lincoln, Lincoln, Nebraska 68588, United States
4. Department of Physics, University of Arkansas, Fayetteville, Arkansas 72701, United States