Nanolaminate-based design for UV laser mirror coatings.
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ABSTRACT: With ever-increasing laser power, the requirements for ultraviolet (UV) coatings increase continuously. The fundamental challenge for UV laser-resistant mirror coatings is to simultaneously exhibit a high reflectivity with a large bandwidth and high laser resistance. These characteristics are traditionally achieved by the deposition of laser-resistant layers on highly reflective layers. We propose a “reflectivity and laser resistance in one” design by using tunable nanolaminate layers that serve as an effective layer with a high refractive index and a large optical bandgap. An Al2O3–HfO2 nanolaminate-based mirror coating for UV laser applications is experimentally demonstrated using e-beam deposition. The bandwidth, over which the reflectance is >99.5%, is more than twice that of a traditional mirror with a comparable overall thickness. The laser-induced damage threshold is increased by a factor of ~1.3 for 7.6?ns pulses at a wavelength of 355?nm. This tunable, nanolaminate-based new design strategy paves the way toward a new generation of UV coatings for high-power laser applications.
SUBMITTER: Zhu M
PROVIDER: S-EPMC7012845 | biostudies-literature | 2020
REPOSITORIES: biostudies-literature
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