Ac Calorimetric Method Of Ultrashort Laser Pulses

The heat transfer and thermophysical properties of thin films, including thermal conductivity and thermal diffusivity, differ from the corresponding bulk material when it comes into microscale regime. Analysis and measurement of thermophysical properties contribute to microscale heat transfer, heat transfer ability and heat dispersion velocity of micro-device and developing new micro-device.First this paper introduces the development of microscale heat transfer from theory, experiment and computer Simulation. Then it analyses the heat transfer mechanism during short-pulse heating of metals and the microscale heat conduction in dielectric thin films. Last it expatiates on the principle of AC calorimetric method and its experimental techniques.To measure the thin film's diffusivity a testing system based on the AC * calorimetric method is set up, in which a laser source is used to heat up the samples. Using the system, the thermal diffusivity of three thin-films with the thickness of 1000 A and 5000 A were measured, respectively. The results show that the thermal diffusivity of thin film is smaller than its corresponding bulk material, and with the decreasing of the thickness, the thermal diffusivity also decreasing.This paper comes from the project of "Microscale heat transfer in micro-sensor",which is the subproject of "Microscale heat transfer in spaceflight technique and information devices" from the National Nature Science Fund...