Details
| Original language | English |
|---|---|
| Title of host publication | 48th Annual Laser Damage Symposium Proceedings - Laser-Induced Damage in Optical Materials 2016 |
| Publisher | SPIE |
| ISBN (electronic) | 9781510604360 |
| Publication status | Published - 6 Dec 2016 |
| Event | 48th Annual Laser Damage Symposium - Laser-Induced Damage in Optical Materials 2016 - Boulder, United States Duration: 25 Sept 2016 → 28 Sept 2016 |
Publication series
| Name | Proceedings of SPIE - The International Society for Optical Engineering |
|---|---|
| Volume | 10014 |
| ISSN (Print) | 0277-786X |
| ISSN (electronic) | 1996-756X |
Abstract
The modeling of the laser-induced damage processes can be divided into thermal and electronic processes. Especially, electronic damage seems to be well understood. In corresponding models, the damage threshold is linked to the excitation of valence electrons into the conduction band, and often the damage is obtained if a critical density of free electrons is exceeded. For the modeling of the electronic excitation, rate equation models are applied which can vary in the different terms representing different excitation channels. According to the current state of the art, photoionization and avalanche ionization contribute the major part to the ionization process, and consequently the determination of laser-induced damage thresholds is based on the calculation of the respective terms. For the theoretical description of both, well established models are available. For the quantitative calculation of the photoionization, the Keldysh theory is used most frequently, and for the avalanche processes the Drude theory is often applied. Both, Drude and Keldysh theory calculations depend on the laser frequency and use a monochromatic approach. For most applications the monochromatic description matches very well with the experimental findings, but in the range of few-cycle pulses the necessary broadening of the laser emission spectrum leads to high uncertainty for the calculation. In this paper, a novel polychromatic approach is presented including photo-and avalanche ionization as well as the critical electron density. The simulation combines different ionization channels in a Monte-Carlo procedure according to the frequency distribution of the spectrum. The resulting influence on the wavelength and material dependency is discussed in detail for various pulse shapes and pulse durations. The main focus of the investigation is concentrated on the specific characteristics in the dispersion and material dependency of the laser-induced damage threshold respecting the polychromatic characteristics of the ultra-short pulse (USP) laser damage.
Keywords
- ionization, laser-induced damage, polychromatic, Ultrafast
ASJC Scopus subject areas
- Materials Science(all)
- Electronic, Optical and Magnetic Materials
- Physics and Astronomy(all)
- Condensed Matter Physics
- Computer Science(all)
- Computer Science Applications
- Mathematics(all)
- Applied Mathematics
- Engineering(all)
- Electrical and Electronic Engineering
Cite this
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- BibTeX
- RIS
48th Annual Laser Damage Symposium Proceedings - Laser-Induced Damage in Optical Materials 2016. SPIE, 2016. 100141C (Proceedings of SPIE - The International Society for Optical Engineering; Vol. 10014).
Research output: Chapter in book/report/conference proceeding › Conference contribution › Research › peer review
}
TY - GEN
T1 - Ultrafast polychromatic ionization of dielectric solids
AU - Jürgens, P.
AU - Jupé, M.
AU - Gyamfi, M.
AU - Ristau, Detlev
PY - 2016/12/6
Y1 - 2016/12/6
N2 - The modeling of the laser-induced damage processes can be divided into thermal and electronic processes. Especially, electronic damage seems to be well understood. In corresponding models, the damage threshold is linked to the excitation of valence electrons into the conduction band, and often the damage is obtained if a critical density of free electrons is exceeded. For the modeling of the electronic excitation, rate equation models are applied which can vary in the different terms representing different excitation channels. According to the current state of the art, photoionization and avalanche ionization contribute the major part to the ionization process, and consequently the determination of laser-induced damage thresholds is based on the calculation of the respective terms. For the theoretical description of both, well established models are available. For the quantitative calculation of the photoionization, the Keldysh theory is used most frequently, and for the avalanche processes the Drude theory is often applied. Both, Drude and Keldysh theory calculations depend on the laser frequency and use a monochromatic approach. For most applications the monochromatic description matches very well with the experimental findings, but in the range of few-cycle pulses the necessary broadening of the laser emission spectrum leads to high uncertainty for the calculation. In this paper, a novel polychromatic approach is presented including photo-and avalanche ionization as well as the critical electron density. The simulation combines different ionization channels in a Monte-Carlo procedure according to the frequency distribution of the spectrum. The resulting influence on the wavelength and material dependency is discussed in detail for various pulse shapes and pulse durations. The main focus of the investigation is concentrated on the specific characteristics in the dispersion and material dependency of the laser-induced damage threshold respecting the polychromatic characteristics of the ultra-short pulse (USP) laser damage.
AB - The modeling of the laser-induced damage processes can be divided into thermal and electronic processes. Especially, electronic damage seems to be well understood. In corresponding models, the damage threshold is linked to the excitation of valence electrons into the conduction band, and often the damage is obtained if a critical density of free electrons is exceeded. For the modeling of the electronic excitation, rate equation models are applied which can vary in the different terms representing different excitation channels. According to the current state of the art, photoionization and avalanche ionization contribute the major part to the ionization process, and consequently the determination of laser-induced damage thresholds is based on the calculation of the respective terms. For the theoretical description of both, well established models are available. For the quantitative calculation of the photoionization, the Keldysh theory is used most frequently, and for the avalanche processes the Drude theory is often applied. Both, Drude and Keldysh theory calculations depend on the laser frequency and use a monochromatic approach. For most applications the monochromatic description matches very well with the experimental findings, but in the range of few-cycle pulses the necessary broadening of the laser emission spectrum leads to high uncertainty for the calculation. In this paper, a novel polychromatic approach is presented including photo-and avalanche ionization as well as the critical electron density. The simulation combines different ionization channels in a Monte-Carlo procedure according to the frequency distribution of the spectrum. The resulting influence on the wavelength and material dependency is discussed in detail for various pulse shapes and pulse durations. The main focus of the investigation is concentrated on the specific characteristics in the dispersion and material dependency of the laser-induced damage threshold respecting the polychromatic characteristics of the ultra-short pulse (USP) laser damage.
KW - ionization
KW - laser-induced damage
KW - polychromatic
KW - Ultrafast
UR - http://www.scopus.com/inward/record.url?scp=85015711751&partnerID=8YFLogxK
U2 - 10.1117/12.2244833
DO - 10.1117/12.2244833
M3 - Conference contribution
AN - SCOPUS:85015711751
T3 - Proceedings of SPIE - The International Society for Optical Engineering
BT - 48th Annual Laser Damage Symposium Proceedings - Laser-Induced Damage in Optical Materials 2016
PB - SPIE
T2 - 48th Annual Laser Damage Symposium - Laser-Induced Damage in Optical Materials 2016
Y2 - 25 September 2016 through 28 September 2016
ER -