Paper
19 November 2013 Near-ultraviolet absorption-annealing effects in HfO2 thin films subjected to continuous-wave laser irradiation at 355 nm
S. Papernov, A. A. Kozlov, J. B. Oliver, T. J. Kessler, B. Marozas
Author Affiliations +
Abstract
Hafnium oxide is the most frequently used high-index material in multilayer thin-film coatings for high-power laser applications ranging from near-infrared to near-ultraviolet. Absorption in this high-index material is also known to be responsible for nanosecond-pulse laser-damage initiation in multilayers. In this work, modification of the near-ultraviolet absorption of HfO2 monolayer films subjected to irradiation by continuous-wave (cw) 355-nm or 351-nm laser light focused to produce power densities of the order of ~100 kW/cm2 is studied. Up to a 70% reduction in absorption is found in the areas subjected to irradiation. Temporal behavior of absorption is characterized by a rapid initial drop on the few-tens-of-seconds time scale, followed by a longer-term decline to a steady-state level. Absorption maps generated by photothermal heterodyne imaging confirm the permanent character of the observed effect. Nanosecond-pulse, 351-nm and 600-fs, 1053-nm laser-damage tests performed on these cw laser-irradiated areas confirm reduction of absorption by measuring up to 25% higher damage thresholds. We discuss possible mechanisms responsible for near-ultraviolet absorption annealing and damage-threshold improvement resulting from irradiation by near-ultraviolet cw laser light.
© (2013) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
S. Papernov, A. A. Kozlov, J. B. Oliver, T. J. Kessler, and B. Marozas "Near-ultraviolet absorption-annealing effects in HfO2 thin films subjected to continuous-wave laser irradiation at 355 nm", Proc. SPIE 8885, Laser-Induced Damage in Optical Materials: 2013, 888504 (19 November 2013); https://doi.org/10.1117/12.2031640
Advertisement
Advertisement
RIGHTS & PERMISSIONS
Get copyright permission  Get copyright permission on Copyright Marketplace
KEYWORDS
Absorption

Continuous wave operation

Near ultraviolet

Annealing

Pulsed laser operation

Thin films

Laser irradiation

Back to Top