1. Department of Physics, University of Colorado, Boulder, Colorado 80309, United States
2. Liquid Crystal Materials Research Center, University of Colorado, Boulder, Colorado 80309, United States
3. Centre for Optical and Electromagnetic Research, Zhejiang University, Hangzhou 310058, People’s Republic of China
4. Department of Electromagnetic Engineering, Royal Institute of Technology, S-100 44 Stockholm, Sweden
5. Renewable and Sustainable Energy Institute, National Renewable Energy Laboratory and University of Colorado, Boulder, Colorado 80309, United States