Quality assessment of variable reflectivity laser mirrors with high laser –induced damage threshold and structural analysis

Document Type : Articles

Authors

• Hasan Ebadian ¹
• omid sheikhi ²
• mahdi mardiha ²

¹ Faculty of Sciences.Malek Ashtar University of Technology.Iran

² Faculty of Applied Sciemces.Malek Ashtar University of Tecknology.Iran

10.30495/jopn.2023.32299.1298

Abstract

We reported the results of an experimental study on the fabrication of a multilayer variable reflectivity laser mirror and the morphological analysis of optical thin film layers. In a design procedure, a series of variable reflectivity laser mirrors are fabricated and characterized with different methods. In this research, based on pulsed solid-state Nd:YAG lasers at 1064 nm, two types of variable reflectivity laser mirrors with (HfO2/SiO2) and (ZrO2/SiO2) materials are fabricated by electron beam evaporation method. The central reflectivity of R0 =30 and 35 % for two super Gaussian orders of n=3 and 4 is manufactured and qualified by ellipsometry and laser beam scan methods. The Laser-induced damage threshold experiments demonstrated that, the VRMs with multilayers of HfO2/SiO2, have a higher Laser-induced damage threshold than ZrO2/SiO2, which was 10 J/cm2 and 7 J/cm2, correspondingly. Also, in a novel and exact FESEM approach, the morphological structure of the VRM thin layers was monitored which gives a deeper insight into the layer structure and helped us to calibrate the PVD device for shaped VRM.

Keywords

• ellipsometry
• Variable Reflectivity Mirrors (VRM)
• PVD
• FESEM
• Laser induced damage threshold (LIDT

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