Pulsed laser ablation of solids and critical phenomena

Bulgakova, N. M.; Bulgakov, Alexander V.; Bourakov, Igor M; Bulgakova, Natalia A.

doi:10.1016/s0169-4332(02)00310-0

Cited by 41 publications

(30 citation statements)

References 13 publications

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“…The non-thermal melting occurs at fluences fairly higher than needed for purely thermal melting process. The melted surface, even if its temperature is far below the thermodynamic critical temperature, inevitably enters the region of metastable states with the subsequent phase explosion as one of probable stabilization mechanisms [17]. The overheated liquid can decay into the gas phase without formation of the critical vapor nucleus [17] so the ejection of small clusters is quite possible.…”

Section: Monatomic Simentioning

confidence: 99%

“…The melted surface, even if its temperature is far below the thermodynamic critical temperature, inevitably enters the region of metastable states with the subsequent phase explosion as one of probable stabilization mechanisms [17]. The overheated liquid can decay into the gas phase without formation of the critical vapor nucleus [17] so the ejection of small clusters is quite possible. More work is needed to be certain about the origin of the cluster ions under these conditions but some observations support the PE mechanism.…”

Section: Monatomic Simentioning

confidence: 99%

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Silicon clusters produced by femtosecond laser ablation: non-thermal emission and gas-phase condensation

2004

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Neutral silicon clusters Sin (up to n = 7) and their cations Si + n (up to n = 10) have been produced by femtosecond laser ablation of bulk silicon in vacuum and investigated using time-offlight mass spectrometry. Two populations of the Si + n clusters with different velocity and abundance distributions in the ablation plume have been clearly distinguished. Possible mechanisms of cluster formation (Coulomb explosion, gas-phase condensation, phase explosion) are discussed.PACS: 52.38. MF; 61.46.+w; 79.20.Ds Femtosecond laser ablation is a rapidly developing technique offering new possibilities in various applications. The fundamental mechanisms that lead to material removal are, however, still poorly understood. The interaction of fs laser pulses with silicon is an example of a complex interplay of thermal and ultrafast, nonthermal processes involved to ablation [1,2,3]. Studies of composition and expansion dynamics of the laser-induced plume can provide a considerable insight into the ablation mechanisms. Several recent experiments on this subject [2,4,5,6] were mainly devoted to the atomic component of the plume though an observation of small silicon clusters was also mentioned [2]. Little is known about silicon cluster formation under ablation with short laser pulses. With ns pulses, low-fluence desorption of Si dimers [7] and small neutral Si n clusters [8] were observed. Desorption of small clusters from both crystalline and nanostructured Si surfaces was induced by using high-energy (6.4 eV) photons [9]. Multiple-charged cluster ions were formed in ps-laser stimulated field evaporation [10]. Recently we reported the first results on the observation of neutral and cationic clusters under femtosecond laser ablation of silicon [11]. In this work, we analyze mechanisms of clusters formation based on measurements of the abundance and velocity distributions. I. EXPERIMENTThe experiments were performed with Si[100] surface under ultrahigh vacuum conditions (∼ 10 −10 mbar). The Si target was irradiated at a 45˚incidence angle using a Ti:sapphire laser (Mai-Tai coupled with a TSA amplifier, Spectra Physics, 80 fs pulse duration, 10 Hz rep- * Fax: +7 3832 343480, Tel.: +7 3832 391045; Electronic address: bulgakov@itp.nsc.ru † Electronic address: ozerov@crmcn.univ-mrs.fr ‡ Electronic address: marine@crmcn.univ-mrs.fr etition rate, up to 30 mJ energy per pulse) operating at 800 nm. A part of the laser beam was selected by an aperture to provide a nearly uniform intensity distribution over the irradiated spot. The target was rotated/translated during measurements to avoid considerable cratering. Some experiments were performed with the fixed target in order to investigate the effect of accumulation of laser pulses at the same spot. The fluence on the target was varied in the range 80-800 mJ/cm 2 . The abundance distributions of neutral and positively charged particles in the laser-ablation plume were studied using a reflectron time-of-flight mass spectrometer. The neutral particles were analyzed using electron impact...

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Section: Monatomic Simentioning

confidence: 99%

Section: Monatomic Simentioning

confidence: 99%

Silicon clusters produced by femtosecond laser ablation: non-thermal emission and gas-phase condensation

2004

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“…In semiconductors, strong levels of electronic excitation lead to bond breaking and lattice destabilization, producing ultrafast phase transitions [20]. At very high excitation intensities, when hot carrier absorption becomes important, a hot electron bath is generated, rapidly coupling to the lattice via electron-phonon collisions, producing layer superheating, phase explosion, or explosive boiling [21][22][23]. These processes are developed in pico-and nanosecond timescales, resulting in the ejection of a plasma plume (Fig.…”

Section: Laser Ablation Mechanismsmentioning

confidence: 99%

Laser Fabrication of Nanoparticles

Caricato

Luches

Martino

2015

Handbook of Nanoparticles

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Lasers are widely used for material processing (cutting, drilling, cleaning, film deposition, etc.). A recent application is for nanoparticle fabrication. Pulsed laser ablation is by far the fastest and clean method to fabricate nanoparticles directly from bulk targets. For this purpose, target ablation is performed in vacuum, in gas atmosphere, or in liquids with fast (nanosecond) and ultrafast (picosecond, femtosecond) laser pulses. Mostly metal but also semiconductor and ceramic nanoparticles were fabricated. In the early stage of this technique, the main problem was the large size distribution of the produced nanoparticles. But the possibility to independently handle laser pulse characteristics (wavelength, power density, pulse duration, etc.) and the accurate control and optimization of the ambient parameters is leading to an efficient tailoring of the nanoparticle size, due also to helpful theoretical and numerical models. A review is presented of the most important studies and of the obtained results.

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“…Among them, phase explosion has been recognized as the dominant mechanism of fs laser ablation of metals [3,7]. In this work, the two-temperature model [8] is formulated for a two-dimensional cylindrical geometry: …”

Section: Theoretical Modellingmentioning

confidence: 99%

“…Accordingly, several models were proposed for numerical simulation of the fs ablation of metals [2][3][4]. However, predicting the topography generated by femtosecond (fs) laser pulses is a challenging task since there are many ambiguities as to the physical mechanisms of material ablation and most of the previously suggested numerical models are one-dimensional for simplicity of computation.…”

Section: Introductionmentioning

confidence: 99%