1. Jiangxi Key Laboratory of Surface EngineeringJiangxi Science and Technology Normal University Nanchang 330013 P. R. China
2. School of Physics and EngineeringShandong Provincial Key Laboratory of Laser Polarization and InformationQufu Normal University Qufu 273165 P. R. China
3. Key Lab of Materials PhysicsAnhui Key Lab of Nanomaterials and NanotechnologyInstitute of Solid State PhysicsChinese Academy of Sciences Hefei 230031 P. R. China