1. Optical Sciences Center, University of Arizona, Tucson, Arizona 85721, USA
2. Department of Physics and Astronomy, and ERC Center for Computational Sciences, Mississippi State University, P.O. Box 5167, Mississippi State, Mississippi 39762-5167, USA
3. Department of Physics, and Center for Materials Research and Technology, and School of Computational Science and Information Technology, Florida State University, Tallahassee, Florida 32306-4350, USA