Features of Circularly Polarized Luminescence of Paramagnetic Garnets $\sf\small Y_3Al_5O_{12}:Tb^3+$ and $\sf\small Y_3Al_5O_{12}:Ho^3+$ in Magnetic Field

Abstract

The spectra of circularly polarized luminescence of the paramagnetic garnets $\sf\small Y_3Al_5O$₁₂:Tb³⁺ and $\sf\small Y_3Al_5O$₁₂:Ho³⁺ in magnetic field have been studied experimentally in the visible range of wavelength for the ⁵D_4̊→ ⁷F₅ transition of the Tb³⁺ ions and for the ⁵S₂→ ⁵I₈ transition of the Ho³⁺ ions. A great difference has been found in the intensities of orthogonal circularly polarized components for a number of luminescence lines. The findings are explained by a mechanism of mixing of electronic states of the Tb³⁺ and Ho³⁺ ions in the matrix of the $\sf\small Y_3Al_5O$₁₂ garnet in an external magnetic field. The results of numerical calculations of the energy spectra of the ⁷F₅3+ ions in a crystalline field of D₂ symmetry are presented.