Optical spectroscopy of La3Ga5SiO14 disordered crystals doped with Fe3+ ions

The circular dichroism, absorption and luminescence spectra of langasite (La3Ga5SiO14) doped with iron ions (Fe) are investigated at temperatures T of 300 and 8 K. Analysis of the data obtained reveals the Fe ions are trivalent. The Fe3+ impurity ions substitute Ga3+ ions and occupy 3f tetrahedral sites. Luminescence from the 4T1 excited state of the dopant was detected at 8 K.