1. Department of Physics
and Astronomy, University of Kansas, Lawrence, Kansas 66045, United States
2. College of Physics, Optoelectronics and Energy, Key Lab of Advanced
Optical Manufacturing Technologies of Jiangsu Province, and Key Lab
of Modern Optical Technologies of Education Ministry of China, Soochow University, Suzhou 215006, China
3. Department of Physics and Astronomy, University of Missouri—Kansas City, Kansas City, Missouri 64110, United States