The photoluminescence spectrum of Ti3+-doped Gd3Sc2Al3O12 observed at 77 K and below consists of a series of zero-phonon lines with vibronic structure and a broad band spanning the wavelength range 650 to 1300 nm. By using time-resolved spectroscopy this spectrum has been shown to have overlapping features due to Cr3+ ions, present as ubiquitous impurities in most garnets, and Ti3+ ions, as the dominant active species in these crystals. The Cr3+ impurities are revealed by the zero-phonon lines at 689.2-690.4 nm with attendant phonon-assisted structure. The broadband with peak at 850 nm is identified with the multiphonon sideband of the 2E→2T2 transition of Ti3+ in trigonally-distorted sites in Gd3Sc2Al3O12.
- garnet substate
- garnet crystals