1. Department
of Chemistry, Rice University, Houston, Texas 77005, United States
2. Laboratory
for Nanophotonics, Rice University, Houston, Texas 77005, United States
3. Department
of Physics and Astronomy, University of New Mexico, Albuquerque, New Mexico 87131, United States
4. Department
of Electrical and Computer Engineering, Rice University, Houston, Texas 77005, United States
5. Nanomedicine and
Nanotoxicology Group, Physics Institute of Sao Carlos, University of Sao Paulo, San Carlos, BR-13560970, Brazil
6. Department
of Physics and Astronomy, Rice University, Houston, Texas 77005, United States