Thermal Emissivity Measurement with Two-temperature Method

Abstract

Thermal emissivity is one of the most important indices used to evaluate thermal emission capability of an object and is essential for characterization of thermal emitters, especially in the field of infrared thermal emission engineering for various applications, including personal thermal management, radiative cooling and heat preservation, infrared stealth, and infrared encryption. However, due to the natural background thermal emissions from the ambient environment and experimental setup, conventional methods generally ignore the background emissions while keeping the temperature of the radiating sample significantly higher than the ambient temperature. Here, we introduce a simple method that enables accurate measurement of emissivity of a given sample without necessitating high temperature through elimination of background emission noise by the difference of the measured emission signals of the sample at two different temperatures.