1. Key Laboratory for Physical Electronics and Devices of the Ministry of Education & Shaanxi Key Lab of Information Photonic TechniqueXi'an Jiaotong University Xi'an 710049 China
2. Guangdong Xi'an Jiaotong University Academy Foshan 528300 China
3. MOE Key Laboratory of Weak‐Light Nonlinear PhotonicsTEDA Applied Physics Institute and School of PhysicsNankai University Tianjin 300457 China
4. Institute of SpectroscopyRussian Academy of Sciences Troitsk Moscow Region 108840 Russia
5. Department of Physics and AstronomySan Francisco State University San Francisco CA 94132 USA