Highly reflective silver mirror enhanced by several dielectric films prepared under the low substrate temperature
Hsing-Yu Wu,
Hong-Wei Chen,
Shao-Rong Huang,
Li-Jen Hsiao,
Ching-Ling Cheng,
Guo-Yu Yu,
Yung-Shin Sun,
Jin-Cherng Hsu
Affiliations
Hsing-Yu Wu
Taiwan Space Agency, Taiwan; National Central University, Center for Astronomical Physics and Engineering, Department of Optics and Photonics, Taoyuan City, 320317, Taiwan; National Yang Ming Chiao Tung University, Institute of Space Systems Engineering, Hsinchu City, 300025, Taiwan
Hong-Wei Chen
Fu Jen Catholic University, Department of Physics, New Taipei City 242062, Taiwan
Shao-Rong Huang
National Central University, Center for Astronomical Physics and Engineering, Department of Optics and Photonics, Taoyuan City, 320317, Taiwan; Diopter Precision Taiwan Co., Ltd., Taoyuan City, 324, Taiwan
Li-Jen Hsiao
National United University, Department of Electrical Engineering, Miao-Li, 36063, Taiwan
Ching-Ling Cheng
Diopter Precision Taiwan Co., Ltd., Taoyuan City, 324, Taiwan
Guo-Yu Yu
Department of Engineering and Technology, School of Computing and Engineering, University of Huddersfield, Queensgate, Huddersfield, HD1 3DH, UK
Yung-Shin Sun
Fu Jen Catholic University, Department of Physics, New Taipei City 242062, Taiwan; Corresponding author.
Jin-Cherng Hsu
National Central University, Center for Astronomical Physics and Engineering, Department of Optics and Photonics, Taoyuan City, 320317, Taiwan; Fu Jen Catholic University, Department of Physics, New Taipei City 242062, Taiwan; Fu Jen Catholic University, Graduate Institute of Applied Science and Engineering, New Taipei City, 242062, Taiwan; Corresponding author.
Optical paths in telescopes frequently incorporate silver mirrors for high sensitivity. Unfortunately, silver mirrors without protective coatings are susceptible to sulfurization and oxidation, compromising their quality. Even with protective layers, insufficient adhesion between the coating and the silver film can lead to peeling, exposing the silver to external environments and affecting its quality. This study aimed to identify dielectric materials with superior adhesion to silver, rendering them ideal choices for silver coating applications. By electron gun evaporation, different dielectric layers were deposited on the top and bottom of the silver film under a substrate temperature below 150 °C. These coatings were composed of materials with desired refractive indices, including aluminum oxide (Al2O3), aluminum-doped silicon, magnesium fluoride (MgF2), and other dielectrics. Following the deposition, a tape adhesion test was conducted to evaluate the bond strength of the samples. X-ray photoelectron spectroscopy (XPS) analysis was carried out to investigate the interaction between silver and its neighboring layers. The results revealed that Al2O3 and MgF2 exhibited exceptional adhesion to silver. Moreover, these multilayer coatings can effectively enhance the reflectance of silver in the visible (VIS) wavelength ranges.
