Analysis on Optical Property and Its Influence in Inverse Estimation of Heat Transport Characteristics for Thin Metallic Films Subjected to Ultra-fast Pulse Laser Heating

• Main Author: 黃永賢
• Other Authors: 林振德
• Format: Others
• Language: zh-TW
• Published: 2004
• Online Access: http://ndltd.ncl.edu.tw/handle/6n6b9a

碩士 === 國立交通大學 === 機械工程系所 === 92 === This thesis investigates the applicability of the linear variation of the reflectivity with the electron temperature when the laser pulse duration is too short to measure the variation of electron temperature directly. A more exact relationship between optical reflectivity and electron temperature is derived, and is brought into an inverse analysis which is performed for simultaneous estimation of both thermal conductivity and the electron-phonon coupling factor for thin metal films subjected to ultra-fast laser heating. Results show that as the change range of the electron temperature is small the linear variation of the reflectivity with the electron temperature can be applied, while at small thickness the applicability of the linear relationship is questionable. Furthermore, the reflectance we get before electron temperature reaches balance between front surface and rear surface is too low at the front surface and is too high at the rear surface, the effect of electron temperature distribution on the reflectance should be addressed in order to obtain more accurate estimation of heat transfer characteristics. In the present study, the reflectivity distribution relates to the thickness of thin film, electron temperature, the photon energy and incident angle are also analyzed.