Infrared femtosecond laser ablation of graphite in high vacuum probed by optical emission spectroscopy

Amoruso, S.; Ausanio, G.; Vitiello, M.; Wang, X.

doi:10.1007/s00339-004-3059-2

Cited by 31 publications

(23 citation statements)

References 22 publications

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“…At both the fluences used, it can be observed a strong segregation of the species, with molecules going slower than the neutral C, C þ going faster, and the C 2 þ component being the fastest, as reported earlier [68]. The apparition of all those species, in this order, confirms molecular dynamics calculations [69].…”

Section: Temporal Pulse Laser Shaping For Diamond-like Carbon Films Dsupporting

confidence: 86%

[INVITED] Control of femtosecond pulsed laser ablation and deposition by temporal pulse shaping

Garrelie

Bourquard

Loir

et al. 2016

Optics & Laser Technology

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Section: Temporal Pulse Laser Shaping For Diamond-like Carbon Films Dsupporting

confidence: 86%

[INVITED] Control of femtosecond pulsed laser ablation and deposition by temporal pulse shaping

Garrelie

Bourquard

Loir

et al. 2016

Optics & Laser Technology

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“…These include C 60 (Mitzner & Campbell 1995;Andersen et al 1996;Hesler et al 1997;Wen et al 1998), carbon clusters (Rohlfing 1988;Amoruso et al 2005), and metal clusters as small as Al 4 − (Frenzel et al 1997;Walther et al 1997;Toker et al 2007). Emission of blackbody radiation has also been shown to be an important cooling mechanism in highly excited C 60 (Andersen et al 1997;Hansen & Echt 1997), C 60 + (Vostrikov et al 2000), fullerene anions (Andersen et al 1997), small carbon clusters (Shinozaki et al 2002;Amoruso et al 2005), and napththalene molecules (Beck et al 1981).…”

Section: Blackbody Emission From Molecules and Clustersmentioning

confidence: 99%

“…Although spectra of individual molecules are shown elsewhere (Mitzner & Campbell 1995;Andersen et al 1996;Wen et al 1998;Rohlfing 1988;Amoruso et al 2005), this spectrum is shown here because it illustrates the emission observed from carbon particles having a range of structures and with different particle sizes. The spectrum in Figure 1 is then the blackbody emission of the sample modified by the overall average emissivity of these particles.…”

Section: Blackbody Emission From Molecules and Clustersmentioning

confidence: 99%

Excitation of Extended Red Emission and Near-Infrared Continuum Radiation in the Interstellar Medium

Duley

2009

ApJ

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Many small molecules including carbon clusters emit blackbody radiation in the visible spectrum when their internal temperature, T, is raised above 2000 K by photoabsorption. Blackbody emission is known to be the dominant cooling mechanism for small dehydrogenated carbon molecules for 1500 < T < 3000 K. The condition that T > 2000 K would be met by interstellar molecules containing 28 carbon atoms, heated by energetic photons from the interstellar radiation field. It is shown here that thermal emission will augment photoluminescent emission in extended red emission (ERE) sources when the UV radiation field is enhanced. In particular, this mechanism provides a simple explanation for observations that show that only stars with T eff > 7000 K excite the ERE. The observation by Witt et al. that photons with energies >10.5 eV are required for the onset of ERE emission can then be interpreted as the condition for the initiation of thermal emission at visible wavelengths. These observational requirements have been combined with laboratory and theoretical data to constrain the emitters of the ERE to dehydrogenated carbon molecules, C N with 20 N 28 atoms. The composition and structure of these molecules is discussed and IR band energies for several possible C N species are provided. These molecules are stable against photodissociation in the interstellar radiation field. It is also shown that dimers of these molecules, (C N ) 2 , may be the species that give rise to the near-infrared continuum first detected by Sellgren. A new effect that might be significant under interstellar conditions involving unimolecular rearrangement reactions in thermally excited molecules is also discussed.

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“…This conclusion is supported by recent measurements of the plume dynamics, in vacuum, after fs infrared ablation of graphite, where plumes with multi-component velocity structures were also observed. 35,36 It is suggested that the first component is associated with an initial burst of highly energetic/electrically excited ablated components, indicative of the enhanced fraction of nonthermal ejection mechanisms compared to ns ablation, and the second with subsequently ejected, slower moving, material which could consist of thermally ejected C atoms and clusters. We suggest that the second wave forms as the material ejected more slowly collides with the back of the dissipating first shock wave.…”

Section: Time Resolved Imaging Of Plume Emissions From Specific Spmentioning

confidence: 99%

Dynamics of confined plumes during short and ultrashort pulsed laser ablation of graphite

et al. 2005

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The optical emission from electronically excited C species in the ablation plume following the short ͑ns͒ and ultrashort ͑fs͒ UV pulsed laser ablation of graphite is studied. Wavelength, time and spatially resolved imaging of the plume, in background pressures of inert gases such as argon and helium, is performed. Analysis of images of optical emission from C +* ions and C 2 * radicals, yielded estimates of the apparent velocity of emitting species, which appear to arise both from the initial ablation event and, in the presence of background gas, mainly from impact excitation. At elevated background pressures of argon ͑P Ar ͒, the formation and propagation of a shock wave is observed for ns pulses, whereas for fs pulses, the propagation of two shock waves is observed. During fs ablation, the first shock wave we associate with an initial burst of highly energetic/electronically excited ablated components, indicative of an enhanced fraction of non-thermal ejection mechanisms when compared with ns ablation. The second shock wave we associate with subsequently ejected, slower moving, material. Concurrent with the plume dynamics investigations, nanostructured amorphous carbon materials were deposited by collecting the ablated material. By varying P Ar from 5 to 340 mTorr, the film morphology could be changed from mirror smooth, through a rough nanostructured phase and, at the highest background pressures for ns pulses, to a low density cluster-assembled material. The evident correlations between the film structure, the mean velocities of the emitting C species, and their respective dependences upon P Ar are discussed for both pulse durations. In addition, we comment on the effect of observed initial plume dynamics on the subsequent C cluster formation in the expanding plume.

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Infrared femtosecond laser ablation of graphite in high vacuum probed by optical emission spectroscopy

Cited by 31 publications

References 22 publications

[INVITED] Control of femtosecond pulsed laser ablation and deposition by temporal pulse shaping

[INVITED] Control of femtosecond pulsed laser ablation and deposition by temporal pulse shaping

Excitation of Extended Red Emission and Near-Infrared Continuum Radiation in the Interstellar Medium

Dynamics of confined plumes during short and ultrashort pulsed laser ablation of graphite

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