1. State
Key Laboratory of Transducer Technology, Key Laboratory of Terahertz
Solid-State Technology, Shanghai Institute of Microsystem and Information
Technology, Chinese Academy of Sciences, Shanghai 200050, China
2. University of Chinese Academy of Sciences, Beijing 100039, China
3. Department
of Materials Science and Engineering, Lehigh University, Bethlehem, Pennsylvania 18015 United States
4. INSERM-UGA U1209, Institut Albert Bonniot, F-38000 Grenoble, France