Dengwei Jing1, Jinwen Shi1, Patrick Meyrueis2, Han Zhou3. 1. International Research Center for Renewable Energy, Xi'an Jiaotong University, Xi'an 710049, China. 2. Photonics Systems Laboratory, University of Strasbourg, 67412 Illkirch, France. 3. Department of Colloid Chemistry, Max Planck Institute of Colloids and Interfaces, Research Campus Golm, 14476 Potsdam, Germany.