| 1. |
- González De Alaiza Martínez, Pedro, et al.
(author)
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Maxwell-consistent, symmetry- and energy-preserving solutions for ultrashort-laser-pulse propagation beyond the paraxial approximation
- 2018
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In: Physical Review A. - 2469-9934 .- 2469-9926. ; 98:4
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Journal article (peer-reviewed)abstract
- We analytically and numerically investigate the propagation of ultrashort tightly focused laser pulses in vacuum, with particular emphasis on Hermite-Gaussian and Laguerre-Gaussian modes. We revisit the Lax series approach for forward-propagating linearly polarized laser pulses, to obtain Maxwell-consistent and symmetry-preserving analytical solutions for the propagation of all field components beyond the paraxial approximation in four-dimensional geometry (space and time). We demonstrate that our solution conserves the energy, which is set by the paraxial-level term of the series. The full solution of the wave equation towards which our series converges is calculated in the Fourier space. Three-dimensional numerical simulations of ultrashort tightly focused pulses validate our analytical development.
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| 2. |
- Martínez, P. González De Alaiza, et al.
(author)
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Modeling the time-dependent electron dynamics in dielectric materials induced by two-color femtosecond laser pulses: Applications to material modifications
- 2021
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In: Physical Review A. - 2469-9934 .- 2469-9926. ; 103:3
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Journal article (peer-reviewed)abstract
- Controlling the electron dynamics during laser-matter interactions is a key factor to control the energy deposition and subsequent material modifications induced by femtosecond laser pulses. One way to achieve this goal is to use two-color femtosecond laser pulses. In this paper, the electron dynamics in dielectric materials induced by two-color femtosecond laser pulses is studied by solving dedicated optical Bloch equations. This model includes photo- and impact ionization, the laser heating of conduction electrons, their recombination to the valence band, and their collisions with phonons. The influence of photon energies, laser intensities, and pulse-to-pulse delay is analyzed. Depending on the interaction process, colors cooperate to excite electrons or drive them independently. For the given laser parameters, an optimal pulse-to-pulse delay is found which enhances significantly the energy deposition into the material, in agreement with experimental observations.
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| 3. |
- Petit, Y., et al.
(author)
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Ultrashort laser induced spatial redistribution of silver species and nano-patterning of etching selectivity in silver-containing glasses
- 2019
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In: Optics Express. - : The Optical Society. - 1094-4087. ; 27:10, s. 13675-13680
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Journal article (peer-reviewed)abstract
- Femtosecond laser-induced spatial redistribution of silver species (ions, clusters. and hole centers) in a silver-containing phosphate glass is investigated by correlative means of near-field scanning optical microscopy (NSOM) images, numerical simulations, chemical micro-probe analysis. and nanoscale spatial profiles after soft etching. In particular, we found that the chemical etching selectivity for nanoscale patterning is strongly dependent upon the irradiation of femtosecond laser due to the spatial redistribution of silver species within the affected area. These results strongly indicate that controlling the distribution of silver species by femtosecond laser irradiation may open new routes for surface nanoscale chemical and/or spatial patterning for the fabrication of 2D surface photonic crystals. (C) 2019 Optical Society of America under the terms of the OSA Open Access Publishing Agreement
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| 4. |
- Smetanina, E., et al.
(author)
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Modeling femtosecond laser-induced electron dynamics in dielectrics by means of optical bloch equations
- 2019
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In: 2019 Conference on Lasers and Electro-Optics Europe and European Quantum Electronics Conference, CLEO/Europe-EQEC 2019. - 9781557528209
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Conference paper (peer-reviewed)abstract
- Modern laser technologies provide high-intensity single- or few-cycle laser pulses which open new doors to study laser-matter interaction processes. To predict new routes towards their active control, advanced theoretical and numerical models are required. When approaching the highly non-linear interaction regimes close to the material damage threshold, the traditional perturbation expansion of the polarization response is not valid anymore and a quantum-mechanical modeling is essential [1-4]. A good candidate to model the electron dynamics within this framework is the Optical Bloch Equations (OBEs) approach, which provides all-order material response within a single self-consistent description. We develop a new OBEs-based model of laser matter-interaction including field-induced ionization, both linear and nonlinear polarization responses leading to high harmonics, impact ionization and various relaxation processes taking place in dielectric materials. Here, we apply our model to describe the electron dynamics induced by an intense femtosecond laser pulse in a dielectric.
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| 5. |
- Smetanina, Evgeniya O., et al.
(author)
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Optical Bloch modeling of femtosecond-laser-induced electron dynamics in dielectrics
- 2020
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In: Physical Review E. - 1539-3755. ; 101:6
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Journal article (peer-reviewed)abstract
- A model based on optical Bloch equations is developed to describe the interaction of femtosecond laser pulses with dielectric solids, accounting for optical-cycle-resolved electron dynamics. It includes the main physical processes at play: photoionization, impact ionization, direct and collisional laser heating, and recombination. By using an electron band structure, this approach also accounts for material optical properties as nonlinear polarization response. Various studies are performed, shedding light on the contribution of various processes to the full electron dynamics depending on laser intensity and wavelength. In particular, the standard influence of the impact ionization process is retrieved.
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| 6. |
- Smetanina, E., et al.
(author)
-
Optical Bloch modeling of femtosecond-laser-induced electron dynamics in dielectrics
- 2020
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In: Physical Review E - Statistical, Nonlinear, and Soft Matter Physics. - 2470-0053 .- 2470-0045. ; 101:6
-
Journal article (peer-reviewed)abstract
- A model based on optical Bloch equations is developed to describe the interaction of femtosecond laser pulses with dielectric solids, accounting for optical-cycle-resolved electron dynamics. It includes the main physical processes at play: photoionization, impact ionization, direct and collisional laser heating, and recombination. By using an electron band structure, this approach also accounts for material optical properties as nonlinear polarization response. Various studies are performed, shedding light on the contribution of various processes to the full electron dynamics depending on laser intensity and wavelength. In particular, the standard influence of the impact ionization process is retrieved.
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