1. State Key Laboratory of Luminescence and ApplicationsChangchun Institute of Optics Fine Mechanics and Physics Chinese Academy of Sciences 3888 Eastern South Lake Road Changchun 130033 P. R. China
2. Institute of PhysicsChinese Academy of Sciences Beijing 100190 P. R. China
3. School of Physical SciencesUniversity of Chinese Academy of Sciences Beijing 100190 P. R. China
4. Department of Physical ChemistryRegional Centre of Advanced Technologies and MaterialsPalacky University Olomouc Šlechtitelů 27 Olomouc 783 71 Czech Republic
5. Department of Materials Science and EngineeringCentre for Functional Photonics (CFP)City University of Hong Kong Kowloon Hong Kong SAR