Photothermal characterization of the thermal properties of materials using four characteristic modulation frequencies in two-layer systems

摘要: A simple photothermal methodology for determining simultaneously and in four different ways the thermal diffusivity effusivity of illuminated layer a two-layer system is presented. The method based on analysis signal whole normalized by corresponding one-layer system. Our approach uses modulation frequencies at which amplitude (phase) passes through unity (zero) reaches its maximum (minimum). It shown that these characteristic are independent effusivities layers, their values can be used to obtain layer. Then, using exact complex expression with experimental data phase, same found. In order show usefulness this approach, applied glassy carbon sample contact three types very thick back layers air, water, glycerine. highest (lowest) accuracy measurement properties corresponds frequency zero (minimum) phase occurs.