1. Department of Bioengineering; Clemson University; Clemson SC 29634 USA
2. Department of Pharmacology and Toxicology; East Carolina University; Greenville NC 27834 USA
3. Department of Physics; Clemson University; Clemson SC 29634 USA
4. Center for Optical Materials Science and Engineering Technologies; Clemson University Clemson; SC 29634 USA