Minimizing the angle of incidence errors in intensity ratio phosphor thermometry

This is the authors' abstract. We don't add key points for this paper.

Intensity ratio–based phosphor thermometry is a promising technique for instantaneous temperature measurement of fast-moving objects. However, its accuracy is limited by the blueshift effects of interference filters induced by angle of incidence (AOI) variations. This is especially problematic for phosphors with significant temperature-dependent emission band shifts. To address this issue, we propose the following two-step method. First, a simulation procedure is developed to evaluate measurement errors induced by AOI variations under different filter sets using the BaMgAl 10 O 17 :Eu 2+ (BAM:Eu) phosphor. Simulation results are carefully analyzed, and a filter set is selected that generates low AOI errors and high temperature sensitivity. Second, an experimental temperature–AOI calibration method is developed by fitting the intensity ratio distribution under different AOIs and temperatures using a bivariate quadratic function. Finally, the intensity ratio–based phosphor thermometry method with the selected filter set and the temperature–AOI calibration is validated via surface temperature measurements on a heated disk. AOI-induced errors up to 25 K and 12 K are effectively removed under stationary and rotating conditions, respectively.