Optical Zeeman effect measurements on isolated and ferromagnetically coupled Nd³⁺ions in weakly doped YVO₄crystals: evidence for lack of crystal field perturbations in ion pair interactions

Abstract

Optical Zeeman effect measurements are performed at liquid helium temperature on Nd3+ ions in weakly doped YVO4 crystals in the range 11 350-11 390 cm-1 of the 4F3/2→ 4I9/2 neodymium transitions. This study provides confirmation that the concentration dependent satellite lines accompanying the optical transitions are due to ferromagnetically coupled pairs of Nd3+ ions in undistorted Y3+ sites of D2d point site symmetry. Nonlinear Zeeman splittings are observed in the range of experimental magnetic fields. These splittings are compared with those simulated from crystal field calculations by introducing the Zeeman Hamiltonian into the secular determinant before diagonalization. A reasonably good agreement between the calculated and experimental g-values is obtained, confirming that the exchange coupled neodymium pairs experience no crystal field perturbations.

Efficient optical pumping of Zeeman spin levels in

“…The latter gives more accurate results when the experimental g-factor values are known, as is the case here. Mehta et al [32] measured a linear Zeeman effect for magnetic fields up to 6 T. This implies that at moderate magnetic field, as the one we use in our experiments (0.3 Tesla), each Kramers' doublet Z 1 and Y 1 can be described by an effective spin S = 1/2. Quadratic splitting due to the mixing of excited Kramers' doublets with Z 1 and Y 1 are three order of magnitude smaller than the linear terms.…”

“…We can thus perform a first order calculation to determine a, b, g, d coefficients by diagonalization of the following spin-Hamiltonian [22,32]:…”

“…We used the following experimental values 4 I 9=2 ðZ 1 Þ : jg ? j ¼ 2:361, jg J j ¼ 0:915 [32]; 4 F 3=2 ðY 1 Þ : jg ? j ¼ 0:28 [26], jg J j ¼ 1:13 [32].…”

High-bandwidth quantum memory protocol for storing single photons in rare-earth doped crystals

“…For a neodymium doping concentration of 0.001%, the absorption coefficient is α = 41 cm −1 and the optical inhomogeneous broadening is 2 = 2π × 2.1 rad GHz [38]. The g tensor has principal values of 2.36 and 0.915 [39]. If we assume a 1 cm long crystal (L = 1 cm) and a Gaussian inhomogeneous spectrum, we find that the storage and retrieval efficiencies can be as high as 97% when optimized over the input pulse shape (cf figure 6).…”

Proposed solid-state Faraday anomalous-dispersion optical filter

“…In a crystal field of this symmetry, the ground state 4 I 9/2 splits into five Kramers doublets (Z 1 -Z 5 ) and the 4 F 3/2 excited state splits into two Kramers doublets (R 1 and R 2 ). Since the transition between Z 1 and R 1 possesses the largest oscillator strength, the other transitions can be reasonably ignored [28][29][30]. Under a homogeneous, constant magnetic field, the ground-and excited-state doublets split into two spin sublevels due to a strong first-order Zeeman interaction.…”