Dispersion relation of Er(NbO3)3 phosphor

Abstract

Dispersion relation is established for Er(NbO3)3 phosphor, which is an excellent candidate for optical thermometry based on thermal effect of Er3+ fluorescence intensity ratio. To achieve it, Er(NbO3)3 phosphor was dispersed into α-bromonaphthalene liquid to form a suspension. Then, refractive index values of the suspension were measured at wavelengths 473, 589.3, 632.8, 980, 1311 and 1553 nm by dropping it onto a plastic sheet. Subsequently, refractive indices of the Er(NbO3)3 phosphor were evaluated from these measured index values using Maxwell-Garnett relation. Finally, based on these Er(NbO3)3 index values, which have an error 0.03, a three-oscillator Sellmeier equation that considers contributions from Nb–O group, plasmons in far UV regime and phonons in infrared region is established. In parallel, a Cauchy dispersion equation is also established. Both equations can well fit the experimental data and the refractive indices predicted by the two equations can be regarded as identical within the error 0.03.