Dynamics of plume and crater formation after action of femtosecond laser pulse

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• 作者：M.B. Agranat ; S.I. Anisimov ; S.I. Ashitkov ; V.V. Zhakhovskii ; N.A. Inogamov ; K. Nishihara ; Yu.V. Petrov ; V.E. Fortov ; V.A. Khokhlov
• 关键词：Ultrashort laser ablation ; Pump-probe ; Molecular dynamics ; Spallation
• 刊名：Applied Surface Science
• 出版年：2007
• 出版时间：30 May 2007
• 年：2007
• 卷：253
• 期：15
• 页码：6276-6282
• 全文大小：817 K

文摘

Using microinterferometric method, a transition in laser plume from the regime with spallation to the regime without spallation is experimentally studied for the first time. The transition occurs when the fluence <a name=""mml12"">a><a style=""text-decoration:none; color:black"" href=""/science?_ob=MathURL&_method=retrieve&_udi=B6THY-4MY0MBK-M&_mathId=mml12&_user=10&_cdi=5295&_rdoc=2&_acct=C000050221&_version=1&_userid=10&md5=1bdbb679330bbcecd59ae5829787aacf"" title=""Click to view the MathML source"">F_inca> of incident radiation exceeds a threshold of “evaporation” <a name=""mml13"">a><a style=""text-decoration:none; color:black"" href=""/science?_ob=MathURL&_method=retrieve&_udi=B6THY-4MY0MBK-M&_mathId=mml13&_user=10&_cdi=5295&_rdoc=2&_acct=C000050221&_version=1&_userid=10&md5=02d223b8f3acadfe96af9928cdd457ff"" title=""Click to view the MathML source"">(F_inc)_eva>. It has been shown previously that the spallation layer is formed at fluence above the ablation threshold <a name=""mml14"">a><a style=""text-decoration:none; color:black"" href=""/science?_ob=MathURL&_method=retrieve&_udi=B6THY-4MY0MBK-M&_mathId=mml14&_user=10&_cdi=5295&_rdoc=2&_acct=C000050221&_version=1&_userid=10&md5=6dbfadba2aca63f0d0b6e0588eb7892a"" title=""Click to view the MathML source"">(F_inc)_abla>. Thus the spallation exists within the limits <a name=""mml15"">a><a style=""text-decoration:none; color:black"" href=""/science?_ob=MathURL&_method=retrieve&_udi=B6THY-4MY0MBK-M&_mathId=mml15&_user=10&_cdi=5295&_rdoc=2&_acct=C000050221&_version=1&_userid=10&md5=aa69b428e1353bfd47af122ec720e40e"" title=""Click to view the MathML source"">(F_inc)_abl<F_inc<(F_inc)_eva>. A laser beam has a maximum fluence <a name=""mml16"">a><a style=""text-decoration:none; color:black"" href=""/science?_ob=MathURL&_method=retrieve&_udi=B6THY-4MY0MBK-M&_mathId=mml16&_user=10&_cdi=5295&_rdoc=2&_acct=C000050221&_version=1&_userid=10&md5=e5fa80fc16e1378c53cfa6a06473e84a"" title=""Click to view the MathML source"">(F_inc)_ca> on the axis of the beam. The threshold <a name=""mml17"">a><a style=""text-decoration:none; color:black"" href=""/science?_ob=MathURL&_method=retrieve&_udi=B6THY-4MY0MBK-M&_mathId=mml17&_user=10&_cdi=5295&_rdoc=2&_acct=C000050221&_version=1&_userid=10&md5=681230303fbc1d2e80aeb31e559535c1"" title=""Click to view the MathML source"">F_eva> separates two cases with qualitatively different morphology: (1) with unbroken shell covering the crater entirely if <a name=""mml18"">a><a style=""text-decoration:none; color:black"" href=""/science?_ob=MathURL&_method=retrieve&_udi=B6THY-4MY0MBK-M&_mathId=mml18&_user=10&_cdi=5295&_rdoc=2&_acct=C000050221&_version=1&_userid=10&md5=a4c6121d27f10eb81e5d2505c2b04c51"" title=""Click to view the MathML source"">F_abl<F_c<F_eva>, and (2) with the shell having an aperture in the center (like the volcano muzzle) if <a name=""mml19"">a><a style=""text-decoration:none; color:black"" href=""/science?_ob=MathURL&_method=retrieve&_udi=B6THY-4MY0MBK-M&_mathId=mml19&_user=10&_cdi=5295&_rdoc=2&_acct=C000050221&_version=1&_userid=10&md5=48eac4fb6f31f98234c53eb6688cec71"" title=""Click to view the MathML source"">F_c>F_eva>.