The optical properties of trivalent chromium ions in La3Ga5SiO14 crystals have been investigated by means of absorption, emission, excitation, and lifetime measurements. The particular intermediate value of the octahedral crystal field Dq/B∼2.5 causes the overlapping of the 4T2 with the 2E and 2T1 levels. This overlap is the origin of Fano resonances in the absorption spectrum and of the simultaneous presence of broadband and narrow-line emissions. Polarized measurements have allowed the determinations of second-order effects such as the tetragonal or orthorhomic distortion of the octahedron of oxygen ions around the chromium ion. Moreover the temperature shift of the peak and the nonexponential decay of the broad emission band are indications of the disorder present in the crystal lattice. All these results produce a fairly complete picture of the energy levels of Cr3+ ions in a typical crystal of the Ca-gallogermanate family. © 1994 The American Physical Society.
Casalboni, M., Luci, A., Grassano, U.m., Mill, B., Kaminskii, A. (1994). Optical spectroscopy of La3Ga5SiO14:Cr3+ crystals. PHYSICAL REVIEW. B, CONDENSED MATTER, 49(6), 3781-3790 [10.1103/PhysRevB.49.3781].
Optical spectroscopy of La3Ga5SiO14:Cr3+ crystals
CASALBONI, MAURO;GRASSANO, UMBERTO MARIA;
1994-01-01
Abstract
The optical properties of trivalent chromium ions in La3Ga5SiO14 crystals have been investigated by means of absorption, emission, excitation, and lifetime measurements. The particular intermediate value of the octahedral crystal field Dq/B∼2.5 causes the overlapping of the 4T2 with the 2E and 2T1 levels. This overlap is the origin of Fano resonances in the absorption spectrum and of the simultaneous presence of broadband and narrow-line emissions. Polarized measurements have allowed the determinations of second-order effects such as the tetragonal or orthorhomic distortion of the octahedron of oxygen ions around the chromium ion. Moreover the temperature shift of the peak and the nonexponential decay of the broad emission band are indications of the disorder present in the crystal lattice. All these results produce a fairly complete picture of the energy levels of Cr3+ ions in a typical crystal of the Ca-gallogermanate family. © 1994 The American Physical Society.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
