Microstructure on Surface of LiNbO₃:Fe Induced by a Single Ultra-Short Laser Pulse

A tightly-focused femtosecond Ti:sapphire laser pulse is used to initiate micro-explosions on the surface and internal to an Fe:LiNbO₃ crystal. The resulting structure is morphologically different from that induced in an isotropic sample such as fused silica. The regular pyramid and irregular pyramid craters on the surface of the sample are produced at different positions of focal points. The craters suggest vaporization of materials in the process of micro-explosion due to the expansion of high temperature plasma. The embossment pyramids on the surface present the dynamical process of large volume material displacements under high temperature and pressure, and re-crystallization of anisotropy crystal materials.