Time-resolved temperature measurements during pulsed laser irradiation

Pulsed laser irradiation of absorbing materials leads to a rapid heating of the surface region and a negligible temperature rise in the bulk of the material. The large temperature gradient results in rapid cooling of the surface by thermal conduction, with cooling rates as large as 10¹⁰ K/s. There is great interest in determining temperatures during pulsed laser induced transformations such as crystallization of amorphous layers, melting and epitaxial regrowth of crystalline layers and ablation. We developed a technique that permits accurate measurement of temperatures with nanosecond resolution at a fixed depth in the sample. Heat-flow analysis is then used to obtain the temperature depth-profile through the layer of interest