1State Key Laboratory of Energy Photon-technology in Western China, Shaanxi Engineering Technology Research Center for Solid State Lasers and Application, Northwest University, Xi’an 710069, China
2International Collaborative Center on Photoelectric Technology and Nano Functional Materials, Provincial Key Laboratory of Photo-electronic Technology, Northwest University, Xi’an 710069, China
3Institute of Photonics & Photon-technology, Northwest University, Xi’an 710069, China