1. Department
of Electrical Engineering, Pennsylvania State University, University Park, Pennsylvania 16802, United States
2. Air Force Research Laboratory, Materials and Manufacturing Directorate (AFRL/RXAN), Wright-Patterson AFB, Dayton, Ohio 45433-7707, United States
3. FEI Company, Hillsboro, Oregon 97124, United States
4. CREOL,
College of Optics and Photonics, University of Central Florida, Orlando, Florida 32816, United States