1. Department of Electrical and Computer Engineering, University of Nebraska-Lincoln, Lincoln, Nebraska 68588, USA
2. Air Force Institute of Technology, Wright-Patterson Air Force Base, Ohio 45433-7765, USA
3. Department of Physics and Astronomy, University of Nebraska-Lincoln, Lincoln, Nebraska 68588, USA
4. Air Force Research Laboratory, Sensors Directorate, Wright Patterson AFB, Ohio 45433, USA
5. KBRwyle, Dayton, Ohio 45431, USA
6. Terahertz Materials Analysis Center, Department of Physics, Chemistry and Biology (IFM), Linköping University, SE 58183, Linköping, Sweden
7. Leibniz Institute for Polymer Research, 01069 Dresden, Germany