1. Beijing
Key Lab of Nanophotonics and Ultrafine Optoelectronic Systems, School
of Materials Science and Engineering, Beijing Institute of Technology, Beijing 100081, P. R. China
2. Beijing
Key Lab of Nanophotonics and Ultrafine Optoelectronic Systems, School
of Physics, Beijing Institute of Technology, Beijing 100081, P. R. China
3. Beijing
Key Lab of Nanophotonics and Ultrafine Optoelectronic Systems, School
of Optoelectronics, Beijing Institute of Technology, Beijing 100081, P. R. China
4. State
Key Lab of Transducer Technology, Chinese Academy of Sciences, Beijing 100081, P. R. China