[1] Natl Changhua Univ Educ, Dept Phys, Changhua 50058, Taiwan
[2] Natl Changhua Univ Educ, Grad Inst Photon, Changhua 50058, Taiwan
[3] Max Planck Inst Quantum Opt, D-85748 Garching, Germany
[4] Natl Cent Univ, Dept Phys, Taoyuan 32001, Taiwan
[5] Max Planck Inst Struct & Dynam Matter, D-22761 Hamburg, Germany
[6] Max Planck Inst Phys Komplexer Syst, D-01187 Dresden, Germany
[7] Ctr Free Electron Laser Sci, D-22761 Hamburg, Germany