Nanolaminate-based design for UV laser mirror coatings

• 作者: Meiping Zhu Nuo Xu Behshad Roshanzadeh S.T.P.Boyd Wolfgang Rudolph Yingjie Chai Jianda Shao
• 来源期刊: 光：科学与应用（英文版）
• 年，卷（期）: 2020,（1）
• 所属期刊栏目: Letter
• 页码范围: 12-17
• 页数: 6页
• 语种: 英文

摘要

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.