Method for obtaining a characterisation of a block of material by active pyrometry, said block of material comprising at least two superposed layers, a superficial layer of small thickness placed on a thick substrate, said superficial layer being raised to a set initial temperature, characterized in that it comprises at least the following steps: - a first step consisting in heating at least one set zone of the surface of said superficial layer of material using a salvo of laser pulses ( tir 1 - tir 10), the repetition frequency of said laser pulses ( tir 1 - tir 10) being chosen sufficiently high and their duration sufficiently short that the material of said superficial layer undergoes a plurality of thermal cycles consisting of a rapid rise in temperature when the material is exposed to said laser pulses ( tir 1 - tir 10), followed by a slow decrease in temperature between two laser pulses, not allowing said initial temperature to be returned to, and that the material accumulates heat from one thermal cycle to the next so that it is heated over a sufficient thickness that all the thickness of the thin superficial layer is concerned; - a second step consisting in collecting all or some of the thermal radiation emitted by the surface of said material; - a third step consisting in measuring at least some of said thermal radiation using a sensor; - a fourth step consisting in determining the variation in the temperature of the surface of the superficial layer from the thermal radiation measured by said sensor and processed by a system for acquiring and processing the signal; - and a fifth step consisting in analysing preset time-dependent regimes by comparing the measurements acquired by the system for acquiring and processing the signal with theoretical values given by the heat equation adapted to the physical properties of said material, and by making these two series of values correspond by varying at least one physical parameter associated with said material, said physical parameter being the thickness of the superficial layer, its thermal conductivity, the thermal resistance between two layers of materials, the absorption coefficient and/or the density of said superficial layer, so as to derive therefrom preset thermo-physical properties allowing said characterisation of the superficial layer. - a first step consisting in heating at least one set zone of the surface of said superficial layer of material using a salvo of laser pulses ( tir 1 - tir 10), the repetition frequency of said laser pulses ( tir 1 - tir 10) being chosen sufficiently high and their duration sufficiently short that the material of said superficial layer undergoes a plurality of thermal cycles consisting of a rapid rise in temperature when the material is exposed to said laser pulses ( tir 1 - tir 10), followed by a slow decrease in temperature between two laser pulses, not allowing said initial temperature to be returned to, and that the material accumulates heat from one thermal cycle to the next so that it is heated over a sufficient thickness that all the thickness of the thin superficial layer is concerned; - a second step consisting in collecting all or some of the thermal radiation emitted by the surface of said material; - a third step consisting in measuring at least some of said thermal radiation using a sensor; - a fourth step consisting in determining the variation in the temperature of the surface of the superficial layer from the thermal radiation measured by said sensor and processed by a system for acquiring and processing the signal; - and a fifth step consisting in analysing preset time-dependent regimes by comparing the measurements acquired by the system for acquiring and processing the signal with theoretical values given by the heat equation adapted to the physical properties of said material, and by making these two series of values correspond by varying at least one physical parameter associated with said material, said physical parameter being the thickness of the superficial layer, its thermal conductivity, the thermal resistance between two layers of materials, the absorption coefficient and/or the density of said superficial layer, so as to derive therefrom preset thermo-physical properties allowing said characterisation of the superficial layer.