摘要 |
An object of the invention is to make it possible to correctly and easily measure a thermal diffusivity within a three-layer substance containing an non-metal substance. A non-metal film 1 whose thermophsical properties are unknown is disposed between a first metal film 2 and a second metal film 3, thereby forming a sample having a three-layer structure. The metal films 2 and 3 have predetermined known thermophsical properties, belong to the same sort of substance and have the same thickness. The three-layer substance is disposed on a transparent substrate 4 and is heated from below the second metal film 3, using a picosecond light pulse coming from below and passing through the transparent substrate 4. The light pulse used in the irradiation is converted into a heat in the second metal film 3 during only one picosecond, with such heat diffusing through interface/non-metal film layer/interface and thus arriving at the first metal film 2. By measuring a temperature change on the surface of the first metal film 2, it is possible to perform correct measurement by using the thermoreflectance method formerly suggested in a patent application by the inventors of the present invention.
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