Laser-spot step-heating thermography to measure the thermal diffusivity of solids

Abstract

In this work we show that laser-spot step-heating thermography allows measuring the thermal diffusivity of solids accurately. It consists in illuminating the sample surface with a continuous-wave focused laser spot and recording the time evolution of the surface temperature with an infrared camera. The inherent noise associated to time domain measurements is reduced by applying a very simple image processing procedure. The methodology has been tested on reference samples. Unlike laser spot lock-in (or pulsed) thermography, a step-heating thermography device can be easily put together combining a low-end laser and an entry level IR camera.