In-situ thermoproperties measurement of Pd film deposited onto optical fiber prepared for photothermal reflectance detection

Abstract

This article proposes an in-situ measurement method of the thermal diffusivity and the thermal conductivity of thin film during deposition inside the vacuum chamber based on a photothermal reflectance technique. Our new technique is simple and reasonable, although no adequate conventional instrument exists. A 2.5-mm-diameter FC-ferrule made from zirconium is contained in a vacuum and used to measure the thermoproperties of the thin film deposited on the end surface of the ferrule. The dependence of the thermal diffusivity and the thermal conductivity of the palladium film on the film thickness are demonstrated. These values are shown to be asymptotically adjacent to those of the bulk since the film is thicker. It is also described that the measurement error is increased, since the optical transmissivity of the thin film becomes to be high when the film is too thin.