1. Chemistry and Materials Science Directorate and Physics and Advanced Technologies Directorate, Lawrence Livermore National Laboratory, 7000 East Avenue Livermore California 94550, NSF Center for Biophotonics Science and Technology, University of California, Davis, 4800 Second Avenue, Suite 2600, Sacramento, California 95817, and Department of Physics and Astronomy, Department of Electrical and Computer Engineering, and Laboratory for Nanophotonics, Rice University, 6100 Main Street, Houston, Texas 77005