Ultrashort-pulse laser processing of transparent materials: insight from numerical and semi-analytical models

Bulgakova, Nadezhda M.; Zhukov, V. P.; Mirza, Inam; Meshcheryakov, Yuri P.; Tomáštík, Jan; Michálek, Václav; Haderka, Ondřej; Fekete, Ladislav; Rubenchik, Alexander M.; Федорук, М. П.; Mocek, Tomáš

doi:10.1117/12.2217585

Cited by 9 publications

(8 citation statements)

References 48 publications

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“…Hence, the free-electron temperature is treated as a measure of the average electron energy. The detailed sets of the model equations can also be found elsewhere3652.…”

Section: Methodsmentioning

confidence: 99%

Ultrashort pulse laser ablation of dielectrics: Thresholds, mechanisms, role of breakdown

Mirza

Bulgakova

Tomáštík

et al. 2016

Sci Rep

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133

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In this paper, we establish connections between the thresholds and mechanisms of the damage and white-light generation upon femtosecond laser irradiation of wide-bandgap transparent materials. On the example of Corning Willow glass, evolution of ablation craters, their quality, and white-light emission were studied experimentally for 130-fs, 800-nm laser pulses. The experimental results indicate co-existence of several ablation mechanisms which can be separated in time. Suppression of the phase explosion mechanism of ablation was revealed at the middle of the irradiation spots. At high laser fluences, air ionization was found to strongly influence ablation rate and quality and the main mechanisms of the influence are analysed. To gain insight into the processes triggered by laser radiation in glass, numerical simulations have been performed with accounting for the balance of laser energy absorption and its distribution/redistribution in the sample, including bremsstrahlung emission from excited free-electron plasma. The simulations have shown an insignificant role of avalanche ionization at such short durations of laser pulses while pointing to high average energy of electrons up to several dozens of eV. At multi-pulse ablation regimes, improvement of crater quality was found as compared to single/few pulses.

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“…Hence, the free-electron temperature is treated as a measure of the average electron energy. The detailed sets of the model equations can also be found elsewhere3652.…”

Section: Methodsmentioning

confidence: 99%

Ultrashort pulse laser ablation of dielectrics: Thresholds, mechanisms, role of breakdown

Mirza

Bulgakova

Tomáštík

et al. 2016

Sci Rep

Self Cite

133

View full text Add to dashboard Cite

show abstract

“…where F L = I L T FWHM is the pulse fluence. Equations (15)(16)(17)(18)(19)(20)(21) are used in the numerical simulations described next.…”

Section: Methodsmentioning

confidence: 99%

Bremsstrahlung from the interaction of short laser pulses with dielectrics

2017

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An intense, short laser pulse incident on a transparent dielectric can excite electrons from the valence to the conduction band. As these electrons undergo scattering, both from phonons and ions, they emit bremsstrahlung. Here we present a theory of bremsstrahlung emission appropriate for the interaction of laser pulses with dielectrics. Simulations of the interaction, incorporating this theory, illustrate characteristics of the radiation (power, energy, and spectra) for arbitrary ratios of electron collision frequency to radiation frequency. The conversion efficiency of laser pulse energy into bremsstrahlung depends strongly on both the intensity and duration of the pulse, saturating at values of about 10^{-5}. Depending on whether the intensity is above or below the damage threshold of the material, the emission can originate either from the surface or the bulk of the dielectric, respectively. The bremsstrahlung emission may provide a broadband light source for diagnostics.

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“…where F L = I L T FWHM is the pulse fluence. Equations (15)(16)(17)(18)(19)(20)(21) are used in the numerical simulations described next.…”

Section: Methodsmentioning

confidence: 99%

“…In contrast, bremsstrahlung radiation from CBEs in dielectrics has received little attention [19]. Transient ionization and a range of collision frequencies typify the laser pulse-dielectric interaction.…”

Section: Introductionmentioning

confidence: 99%

Bremsstrahlung Radiation from the Interaction of Short Laser Pulses with Dielectrics

Petrov

Palastro

Peñano

2017

2017 IEEE International Conference on Plasma Science (ICOPS)

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An intense, short laser pulse incident on a transparent dielectric can excite electrons from valence to the conduction band. As these electrons undergo scattering, both from phonons and ions, they emit bremsstrahlung radiation. Here we present a theory of bremsstrahlung emission appropriate for laser pulse-dielectric interactions. Simulations of the interaction, incorporating this theory, illustrate characteristics of the radiation (power, energy and spectra) for arbitrary ratios of electron collision frequency to radiation frequency. The conversion efficiency of laser pulse energy into bremsstrahlung radiation depends strongly on both the intensity and duration of the pulse, saturating at values of about 10 -5 . Depending on whether the intensity is above or below the damage threshold of the material, the emission can originate either from the surface or the bulk of the dielectric respectively. The bremsstrahlung emission may provide a broadband light source for diagnostics.

show abstract

Ultrashort-pulse laser processing of transparent materials: insight from numerical and semi-analytical models

Cited by 9 publications

References 48 publications

Ultrashort pulse laser ablation of dielectrics: Thresholds, mechanisms, role of breakdown

Ultrashort pulse laser ablation of dielectrics: Thresholds, mechanisms, role of breakdown

Bremsstrahlung from the interaction of short laser pulses with dielectrics

Bremsstrahlung Radiation from the Interaction of Short Laser Pulses with Dielectrics

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