Synthesis, characterization and optical properties of LaAlO3:Ho3+ phosphor

Holmium-doped lanthanum aluminate (LaAlO3) powder phosphors have been prepared at furnace temperatures as low as 500 °C by using the combustion route without further calcining treatment. Powder X-ray diffraction and Fourier-transform infrared spectrometry measurements were used to characterize the prepared combustion products, while the optical properties were studied using UV–vis–NIR and photoluminescence spectroscopy. The Judd–Ofelt (J-O) model was applied to obtain the oscillator strengths (f) and three phenomenological intensity parameters. Using J-O parameters (Ω2, Ω4 and Ω6) the radiative transition probabilities (Aab), radiative lifetimes (τR) and branching ratios have been calculated for certain excited states of Ho3+. Using the Fuchtbauer–Ladenberg formula, the stimulated emission cross-sections (σemi) for some interesting transitions, such as 5S2→5I8 and 5F5→5I8 of Ho3+ in LaAlO3, were determined and discussed.