Optical Transition Probabilities for Trivalent Holmium in LaF3 and YAlO3

Abstract

Optical absorption and emission intensities are investigated for trivalent holmium ions in crystals of LaF3 and YAlO3. Oscillator strengths of transitions to all levels up to 40 000 cm−1 were measured from absorption spectra recorded at 300°K. Corresponding oscillator strengths for transitions between J manifolds were calculated using the Judd-Ofelt approach and eigenstates for intermediate coupling. Phenomenological intensity parameters were derived from a least-squares fitting procedure. For both materials, the root-mean-square deviation of observed and calculated oscillator strengths was ±10%. The intensity parameters were also used to calculate the spontaneous emission probabilities and branching ratios from levels of Ho3+ which fluoresce in LaF3 and YAlO3. A table of reduced matrix elements used in the computations is included.