Research Paper: Optimization of Metal-dielectric-quasi Metal High Reflection Mirrors in Infrared Wavelength

Abstract

The purpose of this paper is an optimization of high reflection mirrors in the infrared wavelength. Infrared mirrors, in addition to being one of the main components of carbon dioxide lasers, are widely used in the flexible optical path or beam conduction. In the structure of these high reflection infrared mirrors, metal, dielectric and quasi-metal are used as Glass / Metal / Dielectric / Quasi metal / Air. Separately the design of the high reflection mirror was investigated for each of the metals, dielectric and quasi-metal layers with different materials. In each step, the best type of material is selected based on the highest percentage of reflection. These layers are Silver (with a reflection of 99.87% in the structure of Glass / Metal / Air), magnesium fluoride (with a reflection of 98.31% in the structure of Glass / Ag / MgF 2/ Air), and Germanium (with a reflection of 99.88% in Structure Glass / Ag / MgF 2 / Ge / Air) for metal, dielectric and quasi-metal, respectively. Then, by changing the thickness of each layer, the optimal thicknesses for silver, magnesium fluoride, and germanium were determined to be 100, 550, and 200 nm, respectively. Examining the effect of angles of light incidence, it was observed that the highest average reflection is related to the angle of zero and 99.88%. The coating designs were done by McLeod coating software.

Keywords

• coating
• high reflection
• infrared
• carbon dioxide lasers
• quasi metal