Hao Qian-Qian, Zong Meng-Yu, Zhang Zhen, Huang Hao, Zhang Feng, Liu Jie, Liu Dan-Hua, Su Liang-Bi, Zhang Han. Bismuth nanosheets based saturable-absorption passively Q-switching mid-infrared single-crystal fiber laserJ. Acta Physica Sinica, 2020, 69(18): 184205. DOI: 10.7498/aps.69.20200337