Ultrafast electron microscopy in material science<xref rid="cpb_27_7_070703fn1" ref-type="fn">*</xref><fn id="cpb_27_7_070703fn1"> <label>*</label><p>Project supported by the National Basic Research Program of China (Grant No. 2015CB921300), the National Key Research and Development Program of China (Grant Nos. 2016YFA0300300, 2017YFA0504703, and 2017YFA0302900), the National Natural Science Foundation of China (Grant Nos. 11604372, 11474323, and 11774391), the “Strategic Priority Research Program (B)” of the Chinese Academy of Sciences (Grant No. XDB07020000), and the Scientific Instrument Developing Project of the Chinese Academy of Sciences (Grant No. ZDKYYQ20170002). Z. A. L acknowledges the financial support of the Hundred Talent Program B from CAS.</p> </fn>

Ultrafast electron microscopy in material science* *

Project supported by the National Basic Research Program of China (Grant No. 2015CB921300), the National Key Research and Development Program of China (Grant Nos. 2016YFA0300300, 2017YFA0504703, and 2017YFA0302900), the National Natural Science Foundation of China (Grant Nos. 11604372, 11474323, and 11774391), the “Strategic Priority Research Program (B)” of the Chinese Academy of Sciences (Grant No. XDB07020000), and the Scientific Instrument Developing Project of the Chinese Academy of Sciences (Grant No. ZDKYYQ20170002). Z. A. L acknowledges the financial support of the Hundred Talent Program B from CAS.

Yang Huaixin^{1, 2}, Sun Shuaishuai¹, Zhang Ming^{1, 2}, Li Zhongwen^{1, 2}, Li Zian¹, Xu Peng¹, Tian Huanfang¹, Li Jianqi^{1, 2, 3, †}

(color online) Ultrafast structural dynamics of BNNTs. (a) TEM image of the BNNT assemble supported on a Cu grid and a high-resolution lattice image of a single nanotube. (b) Temporal evolution of the (002) peak positions under a pump fluence of 50 mJ/cm². The changes in the lattice spacings are fitted with a two-exponential function (red curve). (c) Schematic of the three-photon absorption process following the electron–phonon coupling process and the Auger recombination process causing the secondary phonon-emission process. Reprinted from Ref. [46] with permission.