Laser–Matter Interaction in LIBS Experiments

Malvezzi, Andrea Marco

doi:10.1007/978-3-642-45085-3_1

Cited by 5 publications

(10 citation statements)

References 49 publications

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“…Higher power densities usually lead to higher ionization efficiencies, e.g. in multi-photon interactions, where the total ion intensity is proportional to the power density of the ionization laser (Malvezzi, 2014). High-energy, short-wavelength and shortpulse-duration ionization lasers may thus be a valid choice in single-particle ionization.…”

Section: Introductionmentioning

confidence: 99%

“…Once a sufficient density of holes is achieved, the target surface becomes electrostatically unstable, resulting in a Coulomb explosion of ions, the Coulomb explosion takes place in the initial phase and/or phase explosion occurs at a higher stage of multi-photon ionization (Roeterdink et al, 2003). Various mechanisms of the fs-laser ablation (excitation, melting, ablation) were compared to the nanosecond laser ablation (Harilal et al, 2014;Malvezzi, 2014) at different timescales. Substantial atomization and strong cluster formation are the major effects due to the phase and/or Coulomb explosion in the fs-laser ablation (Malvezzi, 2014;Roeterdink et al, 2003;Xu et al, 2000;Zaidi et al, 2010).…”

Section: Introductionmentioning

confidence: 99%

“…Fs lasers are widely used in the fields of micromachining and nanoparticle ablation (Chichkov et al, 1996;Gattass and Mazur, 2008;Malvezzi, 2014;Richard et al, 2013;Tsuji et al, 2003). Fs-laser ablation mechanisms include Coulomb explosion (soft ablation) and phase explosion followed by thermal ablation (strong ablation), depending on fs-laser intensities (Amoruso et al, 1999;Leitz et al, 2011;Roeterdink et al, 2003;Zhou et al, 2007).…”

Section: Introductionmentioning

confidence: 99%

“…Various mechanisms of the fs-laser ablation (excitation, melting, ablation) were compared to the nanosecond laser ablation (Harilal et al, 2014;Malvezzi, 2014) at different timescales. Substantial atomization and strong cluster formation are the major effects due to the phase and/or Coulomb explosion in the fs-laser ablation (Malvezzi, 2014;Roeterdink et al, 2003;Xu et al, 2000;Zaidi et al, 2010). The fs-laser ablation generates more atomic ions than in the nanosecond laser ablation due to rapid energy transfer and also leads to the formation of more ion clusters because of the explosions.…”

Section: Introductionmentioning

confidence: 99%

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Exploring femtosecond laser ablation in single-particle aerosol mass spectrometry

et al. 2018

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Abstract. Size, composition, and mixing state of individual aerosol particles can be analysed in real time using singleparticle mass spectrometry (SPMS). In SPMS, laser ablation is the most widely used method for desorption and ionization of particle components, often realizing both in one single step. Excimer lasers are well suited for this task due to their relatively high power density (10 7 -10 10 W cm −2 ) in nanosecond (ns) pulses at ultraviolet (UV) wavelengths and short triggering times. However, varying particle optical properties and matrix effects make a quantitative interpretation of this analytical approach challenging. In atmospheric SPMS applications, this influences both the mass fraction of an individual particle that is ablated, as well as the resulting mass spectral fragmentation pattern of the ablated material. The present study explores the use of shorter (femtosecond, fs) laser pulses for atmospheric SPMS. Its objective is to assess whether the higher laser power density of the fs laser leads to a more complete ionization of the entire particle and higher ion signal and thus improvement in the quantitative abilities of SPMS. We systematically investigate the influence of power density and pulse duration on airborne particle (polystyrene latex, SiO 2 , NH 4 NO 3 , NaCl, and custom-made core-shell particles) ablation and reproducibility of mass spectral signatures. We used a laser ablation aerosol time-of-flight single-particle mass spectrometer (LAAPTOF, AeroMegt GmbH), originally equipped with an excimer laser (wavelength 193 nm, pulse width 8 ns, pulse energy 4 mJ), and coupled it to an fs laser (Spectra Physics Solstice-100F ultrafast laser) with similar pulse energy but longer wavelengths (266 nm with 100 fs and 0.2 mJ, 800 nm with 100 fs and 3.2 mJ). We successfully coupled the freefiring fs laser with the single-particle mass spectrometer employing the fs laser light scattered by the particle to trigger mass spectra acquisition. Generally, mass spectra exhibit an increase in ion intensities (factor 1 to 5) with increasing laser power density (∼ 10 9 to ∼ 10 13 W cm −2 ) from ns to fs laser. At the same time, fs-laser ablation produces spectra with larger ion fragments and ion clusters as well as clusters with oxygen, which does not render spectra interpretation more simple compared to ns-laser ablation. The idea that the higher power density of the fs laser leads to a more complete particle ablation and ionization could not be substantiated in this study. Quantification of ablated material remains difficult due to incomplete ionization of the particle. Furthermore, the fslaser application still suffers from limitations in triggering it in a useful time frame. Further studies are needed to test potential advantages of fs-over ns-laser ablation in SPMS.

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Section: Introductionmentioning

confidence: 99%