A new experimental apparatus for polarized spectral emissivity measurement in a controlled environment

Abstract

A new experimental apparatus is designed for polarized spectral emissivity measurements of solid material in a controlled environment such as vacuum, oxidization, reducing atmosphere, etc. The sample heater is placed inside a stainless steel chamber, which allows to heat the sample up to 1073 K. The sample heater can be rotated 180° with an electric rotating platform. The stainless steel chamber is equipped with three flow controllable intake valves to simulate different gas atmosphere. A polarization beam splitting cube is placed in front of the window, and the radiance emitted from the specimen surface is divided into P and S polarized radiance. The polarized radiance can be measured from 1200 to 1600 nm by an indium gallium arsenic detector. The effect of radiation of the spherical chamber is calculated and discussed in detail. In order to validate the capability of the apparatus, the polarized spectral emissivity of silicon wafer at 1.5 μm is measured firstly. The result shows an excellent fit with the simulation. Then, the pure iron and silicon carbide is measured respectively in an atmosphere and vacuum environment. The experimental results verify the functionality and repeatability of the apparatus. The uncertainty assessment shows that the relative combined uncertainty of polarized spectral emissivity is no more than 1.92% for the spectral range considered.