Remote LIBS with ultrashort pulses: characteristics in picosecond and femtosecond regimes

Using a container-integrated mobile femtosecond terawatt laser system with integrated detection unit (Teramobile), we have demonstrated remote laser-induced breakdown spectroscopy (R-LIBS) on copper and aluminium samples with targets located at 25 m away from the container. The ability of our laser system to generate pulses in the femtosecond, picosecond and nanosecond regimes allowed us to perform direct comparisons between these three pulse durations. The dependence of the fluorescence signal on laser pulse energy showed a nonlinear behavior with a threshold, which is consistent with the previous observations for laser ablation. Such nonlinear behavior leads to a dependence of the LIBS signal on the temporal-spectral shape of the laser pulse. We showed especially that the transform-limited pulse does not optimize the fluorescence. A properly applied chirp allows an increase of the LIBS signal. Understanding and optimization of the chirp effect would improve the detection limit of the LIBS using a femtosecond laser (Femto-LIBS) and lead to a larger detection distance. Furthermore the use of pulse shaping should enhance the detection specificity for the cases of spectral overlapping between several elements to be identified.

[1]  I. Dors,et al.  Spectroscopic temperature determination of aluminum monoxide in laser ablation with 266-nm radiation. , 1998, Optics letters.

[2]  G. Hagemann.  Wobbling phonon excitations in strongly deformed triaxial nuclei , 2003 .

[3]  S. Michael Angel,et al.  Energy Dependence of Emission Intensity and Temperature in a LIBS Plasma Using Femtosecond Excitation , 2001 .

[4]  D. Body,et al.  Simultaneous elemental analysis system using laser induced breakdown spectroscopy , 2001 .

[5]  I. Schechter.  Laser Induced Plasma Spectroscopy: Α Review of Recent Advances , 1997 .

[6]  Robert Fedosejevs,et al.  Laser-Induced Breakdown Spectroscopy for Microanalysis Using Submillijoule UV Laser Pulses , 2002 .

[7]  Mohamed Chaker,et al.  Ablation of aluminum thin films by ultrashort laser pulses , 2001 .

[8]  S. Winkelmann,et al.  Space- and time-resolved dynamics of plasmas generated by laser double pulses interacting with metallic samples , 2004 .

[9]  L. J. Radziemski,et al.  Review of Selected Analytical Applications of Laser Plasmas and Laser Ablation, 1987-1994 , 1994 .

[10]  S. Mao,et al.  Initiation of an early-stage plasma during picosecond laser ablation of solids , 2000 .

[11]  Gerard Mourou,et al.  Compression of amplified chirped optical pulses , 1985 .

[12]  S. Michael Angel,et al.  Effect of Pulse Delay Time on a Pre-Ablation Dual-Pulse LIBS Plasma , 2001 .

[13]  Dimitra N. Stratis,et al.  LIBS using dual- and ultra-short laser pulses , 2001, Fresenius' journal of analytical chemistry.

[14]  C. H. Ching,et al.  Detection of AlO molecules produced by KrF laser‐ablated Al atoms in oxygen gas and plasma environments , 1995 .

[15]  E. Salmon,et al.  White-Light Filaments for Atmospheric Analysis , 2003, Science.

[16]  C. Fallnich,et al.  Diode-pumped Cr:LiCAF fs regenerative amplifier system seeded by an Er-doped mode-locked fiber laser , 2002 .

[17]  Yaron Silberberg,et al.  Coherent quantum control of two-photon transitions by a femtosecond laser pulse , 1998, Nature.

[18]  J. D. Winefordner,et al.  Fundamentals and Applications of Laser-Induced Breakdown Spectroscopy , 1997 .

[19]  Jin Yu,et al.  Teramobile: A mobile femtosecond-terawatt laser and detection system , 2002 .

[20]  Mark A. Berg,et al.  Some Comparisons of LIBS Measurements Using Nanosecond and Picosecond Laser Pulses , 2001 .

[21]  Silberberg,et al.  Transform-Limited Pulses Are Not Optimal for Resonant Multiphoton Transitions. , 2001, Physical review letters.

[22]  M. Hashida,et al.  Simulation on femto-second laser ablation , 2002 .

[23]  P. Celliers,et al.  Ablation scaling in steady‐state ablation dominated by inverse‐bremsstrahlung absorption , 1984 .

[24]  A W Miziolek,et al.  Ultraviolet laser microplasma-gas chromatography detector: detection of species-specific fragment emission. , 1990, Applied optics.

[25]  F. Dahmani.  Experimental scaling laws for mass‐ablation rate, ablation pressure in planar laser‐produced plasmas with laser intensity, laser wavelength, and target atomic number , 1993 .

[26]  Hiroshi Azechi,et al.  Measurements of mass ablation rate of laser-irradiated target by the face-on x-ray backlighting technique , 1998 .

[27]  Bernard Prade,et al.  Time-evolution of the plasma channel at the trail of a self-guided IR femtosecond laser pulse in air , 2000 .

[28]  B. Chatel,et al.  Competition between sequential and direct paths in a two-photon transition , 2003 .

[29]  J. Owens,et al.  Optical refractive index of air: dependence on pressure, temperature and composition. , 1967, Applied optics.

[30]  Razvan Stoian,et al.  Laser ablation of dielectrics with temporally shaped femtosecond pulses , 2002 .

[31]  Kathy Kincade.  LIBS leaves the lab for field work in industry and defense , 2003 .

[32]  Guillaume Petite,et al.  Ablation threshold dependence on pulse duration for copper , 2002 .