Cold ablation driven by localized forces in alkali halides.
Laser ablation has been widely used for a variety of applications. Since the mechanisms for ablation are strongly dependent on the photoexcitation level, so called cold material processing has relied on the use of high-peak-power laser fluences for which nonthermal processes become dominant; often reaching the universal threshold for plasma formation of ~1 J cm(-2) in most solids. Here we show single-shot time-resolved femtosecond electron diffraction, femtosecond optical reflectivity and ion detection experiments to study the evolution of the ablation process that follows femtosecond 400 nm laser excitation in crystalline sodium chloride, caesium iodide and potassium iodide. The phenomenon in this class of materials occurs well below the threshold for plasma formation and even below the melting point. The results reveal fast electronic and localized structural changes that lead to the ejection of particulates and the formation of micron-deep craters, reflecting the very nature of the strong repulsive forces at play.
1] The Max Planck Institute for the Structure and Dynamics of Matter, and The Hamburg Centre for Ultrafast Imaging, Luruper Chaussee 149, 22761 Hamburg, Germany [2] [3].
Masaki
M
Hada
1] The Max Planck Institute for the Structure and Dynamics of Matter, and The Hamburg Centre for Ultrafast Imaging, Luruper Chaussee 149, 22761 Hamburg, Germany [2].
Dongfang
D
Zhang
1] The Max Planck Institute for the Structure and Dynamics of Matter, and The Hamburg Centre for Ultrafast Imaging, Luruper Chaussee 149, 22761 Hamburg, Germany [2].
Kostyantyn
K
Pichugin
The Max Planck Institute for the Structure and Dynamics of Matter, and The Hamburg Centre for Ultrafast Imaging, Luruper Chaussee 149, 22761 Hamburg, Germany.
Julian
J
Hirscht
1] The Max Planck Institute for the Structure and Dynamics of Matter, and The Hamburg Centre for Ultrafast Imaging, Luruper Chaussee 149, 22761 Hamburg, Germany [2] School of Chemistry, University of Edinburgh, West Mains Road, Edinburgh EH9 3JJ, Scotland.
Michał A
MA
Kochman
The Max Planck Institute for the Structure and Dynamics of Matter, and The Hamburg Centre for Ultrafast Imaging, Luruper Chaussee 149, 22761 Hamburg, Germany.
Stuart A
SA
Hayes
The Max Planck Institute for the Structure and Dynamics of Matter, and The Hamburg Centre for Ultrafast Imaging, Luruper Chaussee 149, 22761 Hamburg, Germany.
Stephanie
S
Manz
The Max Planck Institute for the Structure and Dynamics of Matter, and The Hamburg Centre for Ultrafast Imaging, Luruper Chaussee 149, 22761 Hamburg, Germany.
Regis Y N
RY
Gengler
1] School of Chemistry, University of Edinburgh, West Mains Road, Edinburgh EH9 3JJ, Scotland [2].
Derek A
DA
Wann
Quantum Science and Engineering Center, Kyoto University, Gokasho, Uji, Kyoto 611-0011, Japan.
Toshio
T
Seki
1] The Max Planck Institute for the Structure and Dynamics of Matter, and The Hamburg Centre for Ultrafast Imaging, Luruper Chaussee 149, 22761 Hamburg, Germany [2] Departments of Chemistry and Physics, University of Toronto, 80 St George St, Toronto, Ontario, Canada M5S3H6.
Gustavo
G
Moriena
School of Chemistry, University of Edinburgh, West Mains Road, Edinburgh EH9 3JJ, Scotland.
Carole A
CA
Morrison
Quantum Science and Engineering Center, Kyoto University, Gokasho, Uji, Kyoto 611-0011, Japan.
Jiro
J
Matsuo
1] The Max Planck Institute for the Structure and Dynamics of Matter, and The Hamburg Centre for Ultrafast Imaging, Luruper Chaussee 149, 22761 Hamburg, Germany [2].
Germán
G
Sciaini
1] The Max Planck Institute for the Structure and Dynamics of Matter, and The Hamburg Centre for Ultrafast Imaging, Luruper Chaussee 149, 22761 Hamburg, Germany [2] Departments of Chemistry and Physics, University of Toronto, 80 St George St, Toronto, Ontario, Canada M5S3H6.
R J Dwayne
RJ
Miller