1. Department of Nonproliferation and National Security, Brookhaven National Laboratory, Upton, New York 11793-5000, USA
2. Redlen Technologies, Saanichton, British Columbia V8M 0A5, Canada
3. Department of Applied Physics, NYU School of Engineering, Brooklyn, New York 11201, USA
4. Department of Physics, Ohio State University, Columbus, Ohio 43201, USA
5. Institute of Physics of Charles University, Prague 12116, Czech Republic
6. Department of Mechanical and Nuclear Engineering, Pennsylvania State University, University Park, Pennsylvania 16802, USA
7. Department of Physics, University of Surrey, Surrey GU2 7XH, United Kingdom