1. Department of Physics, Wesleyan University, Middletown, Connecticut 06459, USA
2. U.S. Army DEVCOM–Armaments Center, Watervliet, New York 12189, USA
3. Research School of Physics, Australian National University, Canberra, ACT 2601, Australia
4. Department of Electro-Optics and Photonics, , University of Dayton, Dayton, Ohio 45469, USA
5. Department of Physics, University of Dayton, Dayton, Ohio 45469, USA