Erbium-doped lead fluoride nano-glass-ceramics: application of principal component analysis to upconversion fluorescence spectra for temperature measurement

Principal component analysis is applied to violet, green and red bands of upconversion fluorescence spectra of erbium-doped lead fluoride nano-glass-ceramics at temperatures 44-150 °С. Main physical phenomena are revealed that contribute to the three first principal components. Possibility of resolving the Stark structure of long-wavelength green fluorescence band is supposed on the base of the spectra recording at room and higher temperatures.