Dynamics of femtosecond laser ablation studied with time-resolved x-ray absorption fine structure imaging

We studied the dynamics of the femtosecond laser ablation of aluminum in an energy range well above the ablation threshold with the ultrafast time-resolved x-ray-absorption fine structure imaging technique. Analyzing the spectral structures near the $L$ absorption edge that appeared in one-dimensional images of soft-x-ray absorbance, we successfully identified doubly and singly charged ions, neutral atoms, liquid nanoparticles, and possible atomic clusters in the expanding ablation plume. We also clarified that the ejected particles depend strongly on the laser irradiation intensity. The spatiotemporal evolution of the ablation particles allows us to estimate the spatial distribution of atomic density and the ejection velocity of each type of particle. In particular, we discuss the temporal sequence of the particle ejection in the early stages of plume expansion. Our experimental results strongly support the idea that photomechanical fragmentation and vaporization are dominant mechanisms for the production of liquid nanoparticles and neutral atoms, respectively, in femtosecond laser ablation induced in an irradiation intensity range of ${10}^{14}--{10}^{15}\text{ }\text{W}/{\text{cm}}^{2}$.

[1]  T. Nishikawa,et al.  Soft x-ray imaging system for picosecond time-resolved absorption spectroscopy using a femtosecond-laser-plasma source , 2006 .

[2]  F. Krausz,et al.  Electron emission from metal surfaces by ultrashort pulses: determination of the carrier-envelope phase. , 2003, Physical review letters.

[3]  Laurent J. Lewis,et al.  Molecular-dynamics study of ablation of solids under femtosecond laser pulses , 2003 .

[4]  Vassili Temnov,et al.  Dynamics of ultrashort pulse-laser ablation: equation-of-state considerations , 2002, SPIE High-Power Laser Ablation.

[5]  Roger Kelly,et al.  Critical assessment of thermal models for laser sputtering at high fluences , 1995 .

[6]  H. Padmore,et al.  Metal-insulator transitions in an expanding metallic fluid: particle formation kinetics. , 2003, Physical review letters.

[7]  P. Indelicato,et al.  Relativistic and many-body effects in K, L, and M shell ionization energy for elements with and the determination of the 1s Lamb shift for heavy elements , 1998 .

[8]  Ultrashort X-ray pulses , 1994 .

[9]  R. Singh,et al.  Laser deposition of diamondlike carbon films at high intensities , 1995 .

[10]  Leonid V. Zhigilei,et al.  Microscopic mechanisms of laser ablation of organic solids in the thermal and stress confinement irradiation regimes , 2000 .

[11]  Michel Meunier,et al.  Short-pulse laser ablation of solids: from phase explosion to fragmentation. , 2003, Physical review letters.

[12]  P. A. Atanasov,et al.  Experimental and theoretical investigations of femtosecond laser ablation of aluminum in vacuum , 2005 .

[13]  Costello,et al.  Even-parity autoionizing states in the extreme-ultraviolet photoabsorption spectra of Mg, Al+, and Si2+ , 1994, Physical Review A. Atomic, Molecular, and Optical Physics.

[14]  Salvatore Amoruso,et al.  Generation of silicon nanoparticles via femtosecond laser ablation in vacuum , 2004 .

[15]  Boris N. Chichkov,et al.  Precise laser ablation with ultrashort pulses , 1997 .

[16]  K. Sokolowski-Tinten,et al.  Femtosecond melting and ablation of semiconductors studied with time of flight mass spectroscopy , 1999 .

[17]  M. Chaker,et al.  Critical-point phase separation in laser ablation of conductors. , 2001, Physical review letters.

[18]  C. F. Hague.  3pelectron density of states in liquid aluminum , 1982 .

[19]  Xianfan Xu,et al.  Mechanisms of decomposition of metal during femtosecond laser ablation , 2005 .

[20]  Murakami,et al.  Pulsed-laser irradiated silicon studied by time-resolved x-ray absorption (90-300 eV). , 1986, Physical review letters.

[21]  M. Kandyla,et al.  Femtosecond dynamics of the laser-induced solid-to-liquid phase transition in aluminum , 2007, 2007 Quantum Electronics and Laser Science Conference.

[22]  Ivan Egry,et al.  Reference data for the density and viscosity of liquid aluminum and liquid iron , 2006 .

[23]  D. Young,et al.  Probing particle synthesis during femtosecond laser ablation: initial phase transition kinetics , 2004 .

[24]  A. Tünnermann,et al.  Femtosecond, picosecond and nanosecond laser ablation of solids , 1996 .

[25]  K. Vodopyanov,et al.  Laser-induced electron emission from an Au surface irradiated by single picosecond pulses at λ=2.94 μm. The intermediate region between multiphoton and tunneling effects , 1991 .

[26]  T. Nishikawa,et al.  Transient observation of extended x-ray absorption fine structure in laser-melted Si by using femtosecond laser-produced-plasma soft x ray , 2005 .

[27]  O. Albert,et al.  Comparison between ZnO films grown by femtosecond and nanosecond laser ablation , 2002 .

[28]  J. Costello,et al.  The 2p-subshell photoabsorption spectrum of Al+ in a laser-produced plasma , 1992 .

[29]  R W Falcone,et al.  Properties of liquid silicon observed by time-resolved x-ray absorption spectroscopy. , 2003, Physical review letters.

[30]  M. Meunier,et al.  Thermodynamic pathways to melting, ablation, and solidification in absorbing solids under pulsed laser irradiation , 2006 .

[31]  Masayuki Okoshi,et al.  FEMTOSECOND LASER ABLATION OF FROZEN ACETONE FOR DEPOSITION OF DIAMOND-LIKE CARBON FILMS , 1999 .

[32]  Eitan Grossman,et al.  Synthesis of nanoparticles with femtosecond laser pulses , 2004 .

[33]  T. Ohyanagi,et al.  Time-and-Space Resolved X-Ray Absorption Spectroscopy of Laser-Ablated Si Particles , 1994 .

[34]  Klaus Sokolowski-Tinten,et al.  The physical mechanisms of short-pulse laser ablation , 2000 .

[35]  D. Perez,et al.  Thermodynamic evolution of materials during laser ablation under pico and femtosecond pulses , 2004 .

[36]  Boris N. Chichkov,et al.  Short-pulse laser ablation of solid targets , 1996 .

[37]  K. Sokolowski-Tinten,et al.  Laser-solid interaction in the femtosecond time regime , 1997 .

[38]  G. Tozzi,et al.  L-shell absorption spectrum of neutral aluminum , 1982 .

[39]  M. Balooch,et al.  Properties of GaAs nanoclusters deposited by a femtosecond laser , 2002 .

[40]  T. Nishikawa,et al.  Temporal evolution of soft x-ray pulse emitted from aluminum plasma produced by a pair of Ti:sapphire laser pulses , 1996 .

[41]  A. Ostendorf,et al.  Towards nanostructuring with femtosecond laser pulses , 2003 .

[42]  Klaus Sokolowski-Tinten,et al.  Transient States of Matter during Short Pulse Laser Ablation , 1998 .

[43]  Y. Shimotsuma,et al.  Self-organized nanogratings in glass irradiated by ultrashort light pulses. , 2003, Physical review letters.

[44]  J. A. Catterall,et al.  The soft X-ray L23emission spectrum from liquid aluminium , 1963 .

[45]  Danny Perez,et al.  Ablation of solids under femtosecond laser pulses. , 2002, Physical review letters.

[46]  Paul Gibbon,et al.  Short-pulse laser - plasma interactions , 1996 .

[47]  M. Downer,et al.  Femtosecond time-resolved reflectivity of hydrodynamically expanding metal surfaces. , 1992, Optics letters.

[48]  A. Vogel,et al.  Mechanisms of femtosecond laser nanosurgery of cells and tissues , 2005 .

[49]  P. Kirkpatrick,et al.  Formation of optical images by X-rays. , 1948, Journal of the Optical Society of America.

[50]  C. Gähwiller,et al.  Photoabsorption near the L I I , I I I Edge of Silicon and Aluminum , 1970 .

[51]  F. Bijkerk,et al.  Time‐resolved x‐ray monitoring of laser ablation of and plasma formation from Si , 1986 .

[52]  D. Linde,et al.  Soft X-ray emission from subpicosecond laser-produced plasmas , 1987 .