1. Hansen Experimental Physics Laboratory, Stanford University, Stanford, California 94305, USA
2. Institute for Soldier Nanotechnologies, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, Massachusetts 02139, USA
3. Department of Mechanical and Industrial Engineering, University of Massachusetts, Amherst, Massachusetts 01003, USA
4. Sibley School of Mechanical and Aerospace Engineering, Cornell University, Ithaca, New York 14850, USA
5. Department of Materials Science & Engineering, Texas A&M University, 3003 TAMU, College Station, Texas 77842, USA
6. Department of Chemistry, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, Massachusetts 02139, USA