Vj. Pugh et al., CHARACTERIZATION AND ANALYSIS OF THE 4F-ELECTRONIC STATES OF TRIVALENT HOLMIUM IN YTTRIUM SCANDIUM GALLIUM GARNET, Journal of physics and chemistry of solids, 58(1), 1997, pp. 85-101
The electronic energy-level structure of Ho3+-doped yttrium scandium g
allium garner (Ho:YSGG) is examined over the 0-41,600 cm(-1) spectral
range. Data obtained from a combination of optical absorption, emissio
n and emission excitation spectra measurements are used to locate and
assign 232 of the 465 crystal-field (Stark) levels predicted to be spl
it out of the 45 lowest-energy 4f(10)[SL]J multiplet manifolds of Ho3 in Ho:YSGG. The experimentally characterized energy-level structure i
s analyzed in terms of a model Hamiltonian defined to represent the ma
jor atomic-like (isotropic) interactions that contribute to the LS(ter
m) and J(multiplet) structure of 4f(10)(Ho3+), as well as the anisotro
pic crystal-field interactions that determine the splittings between S
tark levels within the [SL]J multiplet manifolds of 4f(10)(Ho3+). A pa
rameterized form of the model Hamiltonian is used to perform parametri
c fits of calculated to observed energy-level data, and the results ob
tained from these data fits show a root-mean-square deviation of <9 cm
(-1) between the calculated and experimentally determined energies. Th
e crystal-field interaction strengths and anisotropies determined in t
he present study for Ho3+ in YSGG are compared to those determined pre
viously for Ho3+ in YAG (yttrium aluminum garnet, Y3Al5O12) and for Er
3+ in both YSGG and YAG. These comparisons show small but clearly meas
urable differences between the crystal-field interactions operative in
YSGG vs YAG (for both Ho3+ and Er3+ dopant ions). The most significan
t differences between the results obtained from comparative crystal-fi
eld analyses of the Ho3+ vs Er3+ systems are seen in the two-electron
correlation-crystal-field (CCF) contributions to energy-level structur
e. Whereas CCF interactions appear to play a very important role in de
termining the energy-level structures of several 4f(10)(Er3+) multiple
t manifolds, no evidence is found for strong CCF effects on the energy
-level structures of 4f(10)(Ho3+) multiplet manifolds. Copyright (C) 1
996 Elsevier Science Ltd