1. Photonics Laboratory, Munich University of Applied Sciences, Munich, Germany,
2. College of Physics and Optoelectronic Engineering, Shenzhen University, Shenzhen, China
3. College of Sciences, National University of Defense Technology, Changsha, China
4. Photonics Laboratory, Munich University of Applied Sciences, Munich, Germany
5. Institute for Measurement Systems and Sensor Technology, Technical University of Munich, Munich, Germany