575-fs passively mode-locked Yb:CaF2 ceramic laser
Wang Cong1, 2, Hao Qian-Qian1, 2, Li Wei-Wei3, ‡, Huang Hai-Jun4, Wang Shao-Zhao3, Jiang Da-Peng5, 6, Liu Jie1, 2, §, Mei Bing-Chu4, Su Liang-Bi5, 6
       

Absorption spectrum (a) and emission spectrum (b) of the Yb:CaF2 ceramics.