Abstract In this work we deal with samples that move at constant speed and are illuminated by a modulated and focused laser beam. We have obtained a general expression for the surface temperature of these moving samples: it is valid not only for opaque and thermally thick materials, but also for thermally thin and semitransparent samples. Moreover, heat losses by convection and radiation are taken into account in the model. Numerical calculations indicate that the temperature (amplitude and phase) profiles in the directions parallel and perpendicular to the sample motion are straight lines with respect to the distance to the laser spot. The slopes of these straight lines depend on sample speed, modulation frequency and in-plane thermal diffusivity of the sample. Provided the two first experimental parameters are known, the in-plane thermal diffusivity can be retrieved in a simple manner. Measurements performed on materials covering a wide range of thermal diffusivity values, from insulators to good thermal conductors, confirm the validity of these linear methods.

中文翻译：

---

使用激光光斑锁定热成像测量移动样品的面内热扩散率

摘要 在这项工作中，我们处理以恒定速度移动并被调制和聚焦的激光束照射的样品。我们已经获得了这些移动样品的表面温度的一般表达式：它不仅适用于不透明和热厚材料，也适用于热薄和半透明样品。此外，模型中还考虑了对流和辐射的热损失。数值计算表明，平行和垂直于样品运动方向的温度（幅度和相位）曲线相对于到激光光斑的距离是直线。这些直线的斜率取决于样品速度、调制频率和样品的面内热扩散率。假设两个第一个实验参数是已知的，面内热扩散率可以通过简单的方式获得。对涵盖从绝缘体到良好热导体的各种热扩散率值的材料进行的测量证实了这些线性方法的有效性。