We theoretically investigate ultrafast and nonlinear optical properties of graphite thin films based on first-principles time-dependent density functional theory. We first calculate electron dynamics in a unit cell of graphite under a strong pulsed electric field and explore the transient optical properties of graphite. It is shown that the optical response of graphite shows a sudden change from conducting to insulating phase at a certain intensity range of the applied electric field. It also appears as a saturable absorption, the saturation in the energy transfer from the electric field to electrons. We next investigate a light propagation in graphite thin films by solving coupled dynamics of the electrons and the electromagnetic fields simultaneously. It is observed that the saturable absorption manifests in the propagation with small attenuation in the spatial region where the electric field amplitude is about $4 \sim 7 \times 10^{-2}$ V/Angstrom.
Determination of van der Waals thin film thickness via characteristic X-ray photon yield
National Key Laboratory of Science and Technology on Vacuum Electronics, School of Electronic Science and Engineering, University of Electronic Science and Technology of China（电子科技大学电子科学与工程学院真空电子学科学与技术国家重点实验室）；Department of Applied Physics, Xian University of Technology, Xian 710048, China（西安理工大学应用物理系）
Transient Pauli blocking in a InN film as a mechanism for broadband ultrafast optical switching
Global Center for Science and Engineering (GCSE), Faculty of Science and Engineering, Waseda University（早稻田大学理工学部）；Graduate School of Advanced Science and Engineering, Waseda University（早稻田大学先进理工学研究科）；Graduate School of Science and Engineering, Aoyama Gakuin University（青山学院大学理工学府）；Institute for Molecular Science（分子科学研究所）；The Graduate University for Advanced Studies (SOKENDAI)（综合研究大学院大学）；National Metrology Institute of Japan (NMIJ), National Institute of Advanced Industrial Science and Technology (AIST)（产业技术综合研究所国家计量标准研究所）
