An experimental study for assessment of the applicability of laser- induced second harmonic generation (SHG) for measurement of temperatures of hot metallic surfaces will be carried out. The immediate goal of this research is to obtain sufficient data to either eliminate SHG as a candidate diagnostic or create further interest in the development of SHG thermometry. In this study, the main surface of interest will be platinum (rough and polished surfaces) deposited on a tantalum or ceramic substrate. Three separate research tasks will be performmed. First, a repeatable calibration plot of SHG signal versus temperature at surface temperatures from 300 to 1000 K will be sought using samples heated in an electric furnace, with (hopefully) demonstration that the relative SHG signal is independent of surface roughness. Next, the calibration plot will be extended to 1800 K in either a high- temperature furnace or a combustion environment. Finally, dynamic response of the SHG measurement technique will be investigated. The ultimate goal of the proposed research direction is development of SHG thermometry for practical high-temperature applications in the fields of combustion, heat transfer, and materials processing, with particular application to on-line control of manufacturing facilities.
