Temperature effects on the 1.0 and 1.3 μm emission lines of Nd ³⁺ in a LaSc ₃(BO ₃) ₄ crystal host

A detailed investigation of the temperature effect on widths and shifts of the spectral lines of Nd ³⁺ in LaSc ₃(BO ₃) ₄ has been performed. The spectral lines investigated correspond to the inter-Stark transitions R ₁→Y ₃ (1062 nm) and R ₁→Z ₄ (1344 nm) within the ⁴F _3/2→ ⁴I _11/2 and ⁴F _3/2→ ⁴I _13/2 intermanifold transitions, respectively. The widths of these lines and their shifts have been measured as a function of temperature. The linewidths are found to increase with increasing temperature for both transitions; the 1062 nm line shifts to the longer wavelengths, whereas the 1344 nm line shifts to the shorter wavelengths. The theory of phonon-ion interactions has been employed to explain the temperature dependencies of widths and shifts. These interactions give rise to the phonon relaxation processes that are responsible for both the broadening and shifts of the spectral lines.