光声技术在固体材料热扩散率测量中的应用

光声（光热）效应是由于物质吸收一强度随时间变化的光束而被时变加热时所引起的一系列热效应和声效应，研究了这些热效应和声效应，可以获得物质的热学和学学性质，光声技术正是探测由于吸收光辐射后样品的微小温度变化所引起的周围气体压力变化，具有灵敏度高、操作方便、应用广泛等独特的优点，已成为研究物质光谱特性、热学性质等的独特有力手段，文章主要介绍了光声技术在固体热扩散率测量中的原理及常规应用方法。

APPLICATION OF PHOTOACOUSTICS IN MEASURING THE THERMAL DIFFUSITIVITY OF SOLIDS

When a sample absorbs light radiation which varies with time, it is heated and thus a series of thermal and acoustic effects, called photoacoustic (photothermal)effects, occur. Through studying these effects, one can derive the thermal or optical properties of the sample. In photoacoustics measurements the gas pressure variation around the sample, which is caused by temperature variation in the sample surface due to absorption of light radiation, is detected. Photoacoustics is unique and powerful in studying the spectra and thermal properties of solids due to its high sensitivity, easy management, and wide use. In this paper the principles of photoacoustics as well as its application in measuring the thermal diffusitivity of solid materials are introduced.