Role of wavelength in photocarrier absorption and plasma formation threshold under excitation of dielectrics by high-intensity laser field tunable from visible to mid-IR
| Autor: | E. O. Smetanina, Fedor Potemkin, Guillaume Duchateau, E. A. Migal, E. I. Mareev |
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| Rok vydání: | 2020 |
| Předmět: |
0301 basic medicine
Materials science Nonlinear optics Electronic properties and materials lcsh:Medicine Photoionization Dielectric Article law.invention 03 medical and health sciences 0302 clinical medicine Ultrafast photonics law Free carrier absorption Absorption (electromagnetic radiation) lcsh:Science Multidisciplinary lcsh:R Rate equation Laser-produced plasmas Laser Wavelength 030104 developmental biology lcsh:Q Atomic physics 030217 neurology & neurosurgery Excitation |
| Zdroj: | Scientific Reports Scientific Reports, Vol 10, Iss 1, Pp 1-10 (2020) |
| ISSN: | 2045-2322 |
| Popis: | The development of high power mid-IR laser applications requires a study on laser induced damage threshold (LIDT) in the mid-IR. In this paper we have measured the wavelength dependence of the plasma formation threshold (PFT) that is a LIDT precursor. In order to interpret the observed trends numerically, a model describing the laser induced electron dynamics, based on multiple rate equations, has been developed. We show both theoretically and experimentally that PFT at mid-IR wavelengths is controlled by a transition from weak- to strong-field regime of free carrier absorption. In the case of MgF\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$_2$$\end{document}2 this transition occurs around 3–4 \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$\upmu$$\end{document}μm corresponding to the region of the lowermost PFT. The region of the uppermost PFT is reached around 1 \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$\upmu$$\end{document}μm and is governed by an interplay of photoionization and weak-field free carrier absorption which manifests itself in both MgF\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$_2$$\end{document}2 and SiO\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$_2$$\end{document}2. The PFT observed in considered materials exhibits a universal dependence on the excitation wavelength in dielectrics. Thus, the presented results pave the route towards efficient and controllable laser-induced material modifications and should be of direct interest to laser researchers and application engineers for prevention of laser-induced damage of optical components in high-intensity mid-IR laser systems. |
| Databáze: | OpenAIRE |
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