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Title: A high accuracy femto-/picosecond laser damage test facility dedicated to the study of optical thin films

Journal Article · · Review of Scientific Instruments
DOI:https://doi.org/10.1063/1.3677324· OSTI ID:22063759
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  1. Institut Fresnel, CNRS, Aix-Marseille Universite, Ecole Centrale Marseille, Campus de St Jerome, 13013 Marseille (France)

A laser damage test facility delivering pulses from 100 fs to 3 ps and designed to operate at 1030 nm is presented. The different details of its implementation and performances are given. The originality of this system relies the online damage detection system based on Nomarski microscopy and the use of a non-conventional energy detection method based on the utilization of a cooled CCD that offers the possibility to obtain the laser induced damage threshold (LIDT) with high accuracy. Applications of this instrument to study thin films under laser irradiation are presented. Particularly the deterministic behavior of the sub-picosecond damage is investigated in the case of fused silica and oxide films. It is demonstrated that the transition of 0-1 damage probability is very sharp and the LIDT is perfectly deterministic at few hundreds of femtoseconds. The damage process in dielectric materials being the results of electronic processes, specific information such as the material bandgap is needed for the interpretation of results and applications of scaling laws. A review of the different approaches for the estimation of the absorption gap of optical dielectric coatings is conducted and the results given by the different methods are compared and discussed. The LIDT and gap of several oxide materials are then measured with the presented instrument: Al{sub 2}O{sub 3}, Nb{sub 2}O{sub 5}, HfO{sub 2}, SiO{sub 2}, Ta{sub 2}O{sub 5}, and ZrO{sub 2}. The obtained relation between the LIDT and gap at 1030 nm confirms the linear evolution of the threshold with the bandgap that exists at 800 nm, and our work expands the number of tested materials.

OSTI ID:
22063759
Journal Information:
Review of Scientific Instruments, Vol. 83, Issue 1; Other Information: (c) 2012 American Institute of Physics; Country of input: International Atomic Energy Agency (IAEA); ISSN 0034-6748
Country of Publication:
United States
Language:
English