Fiber Bragg grating-based temperature sensor for neutral gas in capacitively coupled plasmas

摘要

A fiber Bragg grating (FBG) has been utilized in capacitively coupled plasmas (CCP) for thermometry of neutral gas. We studied the effects of high frequency and low frequency power on radial distribution of neutral gas temperature. The result shows that the neutral gas temperature increases with increasing high frequency power. However, the presence of low frequency power will decrease the neutral gas temperature. Particularly, we eliminated the effect of ion bombardment on temperature measurement by studying axial distribution near plasma–sheath boundary. With features of immune to electromagnetic interference, high precision, and spatial resolving power, the FBG is a commendable candidate for CCP or other radio-frequency plasmas thermometry in both laboratory and industry.