Paper

Formation of high-aspect-ratio nanocavity in LiF crystal using a femtosecond of x-ray FEL pulse

Tominaga, Aki, Cerantola, Valerio, Mohacsi, István, Inogamov, Nail A, Appel, Karen, Shepelev, Vadim, Vozda, Vojtech, Jan-Patrick Schwinkendorf, Chuprov, Petr, Pikuz, Tatiana A, Khokhlov, Victor V, Preston, Thomas R, Makarov, Sergey S, Rode, Andrei V, Zastrau, Ulf, Makita, Mikako, Grigoryev, Sergey A, Chalupsky, Jaromir, Perov, Eugene, Shobu, Takehisa, Kodama, Ryosuke, Pikuz, Sergey A, Juodkazis, Saulius, Burian, Tomas, Juha, Libor, Nakatsutsumi, Motoaki, Petrov, Yuri V, Rapp, Ludovic, Konopkova, Zuzana, Hajkova, Vera, Brambrink, Erik, Ozaki, Norimasa, Zhakhovsky, Vasily V

2024

Overview

Sub-picosecond optical laser processing of metals is actively utilized for modification of a heated surface layer. But for deeper modification of different materials a laser in the hard x-ray range is required. Here, we demonstrate that a single 9-keV x-ray pulse from a free-electron laser can form a um-diameter cylindrical cavity with length of ~1 mm in LiF surrounded by shock-transformed material. The plasma-generated shock wave with TPa-level pressure results in damage, melting and polymorphic transformations of any material, including transparent and non-transparent to conventional optical lasers. Moreover, cylindrical shocks can be utilized to obtain a considerable amount of exotic high-pressure polymorphs. Pressure wave propagation in LiF, radial material flow, formation of cracks and voids are analyzed via continuum and atomistic simulations revealing a sequence of processes leading to the final structure with the long cavity. Similar results can be produced with semiconductors and ceramics, which opens a new pathway for development of laser material processing with hard x-ray pulses.

• Publisher: Cornell University Library, arXiv.org
• Subject: Cylindrical plasmas / Cylindrical waves / Elastic waves / Free electron lasers / High aspect ratio / Laser beam heating / Laser damage / Laser processing / Lasers / Surface layers