1. State Key Laboratory of Infrared PhysicsShanghai Institute of Technical PhysicsChinese Academy of Sciences200083 ShanghaiChina
2. State Key Laboratory of Functional Materials for InformaticsShanghai Institute of Microsystem and Information TechnologyChinese Academy of Sciences200050 ShanghaiChina
3. Photonic Laboratory, Department of Microtechnology and NanoscienceChalmers University of TechnologyS‐412 96 GöteborgSweden
4. State Key Laboratory of Advanced Optical Communication Systems and NetworksCenter of Quantum Information Sensing and ProcessingShanghai Jiao Tong UniversityShanghai 200240China
5. Key Laboratory of Terahertz Solid State TechnologyCAS, Shanghai Institute of Microsystem and Information TechnologyChinese Academy of Sciences200050 ShanghaiChina
6. Key Laboratory of Polar Materials and DevicesEast China Normal University200062 ShanghaiChina