Measuring the thermal diffusivity and conductivity of thermal insulators using laser-spot step-heating thermography

In laser-spot step-heating thermography the sample surface is illuminated by a focused laser beam while the surface temperature rise is monitored by an infrared video camera. By analysing the temperature profile at several instants after the laser beam is switched on, the in-plane thermal diffusivity can be obtained. In this work, we show that in thermal insulators heat conduction to the surrounding gas, which is typically neglected in this kind of experiments, plays a significant role and allows determining both thermal diffusivity and conductivity simultaneously.

Automated summary

In laser-spot step-heating thermography, a laser beam is focused on the sample surface while the infrared video camera monitors the surface temperature rise. By analyzing the temperature profile at different time points after turning on the laser beam, the in-plane thermal diffusivity can be determined. This study shows that in thermal insulators, heat conduction to the surrounding gas, usually neglected in these experiments, plays a significant role in determining both thermal diffusivity and conductivity simultaneously.