A simple thermographic model has been developed that accurately describes the surface temperature response of a panel with flat bottom holes of different depths and diameters to a short heat pulse. This model assumes that a thin layer of material absorbs a radiant pulse of duration τ and that it subsequently cools off due to normal and lateral diffusion of the deposited energy into the bulk of the material. The model takes into account other experimental parameters such as sample thickness, density, specific heat, in-plane and out-of-plane thermal conductivity and defect size and depth. In this paper we present experimental and modeling results on an aluminum panel with flat bottom holes of different radii and depths. The effects of heat pulse duration will be presented and discussed.