Optical properties of sapphire in its opacity range

Abstract

We have studied the reflection spectrum of leucosapphire in the range of 2.5–25.0 μm. Based on the analysis of the known frequency and temperature dependences of the absorption coefficient in the range of 2.5–7.0 μm, its extrapolation to the range of 10.6 μm has been performed. We have shown that the absorption coefficient in the range of 10.6 μm and in the temperature interval 300–2300 K can be evaluated as β = (2–3) × 10⁴ cm^–1. It has also been shown that the value of this characteristic correlates with the results of investigations of the action of a powerful radiation pulse of a СО₂ laser on the surface of anodized aluminum. These data can be used in the development of technologies of laser processing of articles made of sapphire and ceramics based on aluminum oxide, as well as anodized articles made of aluminum alloys.