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Title: Wavelength dependence of femtosecond laser-induced damage threshold of optical materials

An experimental and numerical study of the laser-induced damage of the surface of optical material in the femtosecond regime is presented. The objective of this work is to investigate the different processes involved as a function of the ratio of photon to bandgap energies and compare the results to models based on nonlinear ionization processes. Experimentally, the laser-induced damage threshold of optical materials has been studied in a range of wavelengths from 1030 nm (1.2 eV) to 310 nm (4 eV) with pulse durations of 100 fs with the use of an optical parametric amplifier system. Semi-conductors and dielectrics materials, in bulk or thin film forms, in a range of bandgap from 1 to 10 eV have been tested in order to investigate the scaling of the femtosecond laser damage threshold with the bandgap and photon energy. A model based on the Keldysh photo-ionization theory and the description of impact ionization by a multiple-rate-equation system is used to explain the dependence of laser-breakdown with the photon energy. The calculated damage fluence threshold is found to be consistent with experimental results. From these results, the relative importance of the ionization processes can be derived depending on material properties and irradiation conditions. Moreover, the observed damage morphologiesmore » can be described within the framework of the model by taking into account the dynamics of energy deposition with one dimensional propagation simulations in the excited material and thermodynamical considerations.« less
Authors:
; ;  [1] ; ; ; ; ; ;  [2]
  1. Aix-Marseille Université, CNRS, Centrale Marseille, Institut Fresnel UMR 7249, 13013 Marseille (France)
  2. Laser Research Center, Vilnius University, Saulétekio aléja 10, LT-10223 Vilnius (Lithuania)
Publication Date:
OSTI Identifier:
22412906
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Applied Physics; Journal Volume: 117; Journal Issue: 22; Other Information: (c) 2015 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSICS; COMPARATIVE EVALUATIONS; COMPUTERIZED SIMULATION; DIELECTRIC MATERIALS; ENERGY ABSORPTION; ENERGY GAP; ENERGY LOSSES; EV RANGE; FREQUENCY DEPENDENCE; IRRADIATION; MORPHOLOGY; NUMERICAL ANALYSIS; PARAMETRIC AMPLIFIERS; PHOTOIONIZATION; PHOTONS; SURFACES; THIN FILMS