Nano-indentation and laser-induced damage testing in optical multilayer-dielectric gratings [Nanomechanics and laser-induced damage in optical multilayer dielectric gratings]

Journal Article · Thu Mar 16 00:00:00 EDT 2017 · Applied Optics

DOI:https://doi.org/10.1364/AO.56.002494· OSTI ID:1357217

Mehrotra, K. ^[1]; Taylor, B. N. ^[1]; Kozlov, A. A. ^[1]; Papernov, S. ^[1]; Lambropoulos, J. C. ^[1]

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1. Univ. of Rochester, Rochester, NY (United States)

Here, we demonstrate how a nanomechanical test can be used to generate metrics to complement laser-induced–damage testing (LIDT) measurements and show that differences in optical performance of the gratings (arising from changes in cleaning process and/or fabrication methods) can be related to their mechanical reliability. Data are presented on LIDT measurements in diffractive gratings of silica deposited on optical multilayers. The nano-indentation response of the diffraction gratings is measured in a new mode that allows for the extraction of a measurable metric characterizing the brittleness of the gratings, as well as their ductility. We show that lower LIDT’s are positively correlated with an increased grating brittleness, and therefore identify a nanomechanical approach to describe LIDT’s. We present extensive numerical simulations of nano-indentation tests and identify different deformation modes including stretching, shear concentration, and bending as precursors to mechanical failure in the nano-indentation test. The effects of geometrical inhomogeneities on enhanced stress generation in these gratings are specifically examined and addressed.

• Research Organization: Univ. of Rochester, NY (United States). Lab. for Laser Energetics
• Sponsoring Organization: USDOE National Nuclear Security Administration (NNSA)
• Contributing Organization: Laboratory for Laser Energetics, University of Rochester
• Grant/Contract Number: NA0001944
• OSTI ID: 1357217
• Alternate ID(s): OSTI ID: 1346875
• Report Number(s): 2016-3, 1337; APOPAI; 2016-3, 1337, 2291
• Journal Information: Applied Optics, Vol. 56, Issue 9; ISSN 0003-6935
• Publisher: Optical Society of America (OSA)
• Country of Publication: United States
• Language: English

Related Subjects

42 ENGINEERING
36 MATERIALS SCIENCE
diffraction gratings
silica
laser materials processing
other properties