Photostimulation induced persistent luminescence in Y_3Al_2Ga_3O_12:Cr^3+

Cr3+-activated Y3Al2Ga3O12 garnet (YAGG:Cr3+) persistent phosphor has been recently reported as a potential candidate material for in vivo imaging application. Temperature dependence of photoluminescence (PL) spectra and thermostimulated luminescence (TSL) glow curves with several conditions, especially photostimulation wavelength dependence, were carefully investigated with the perspective of deep trap utilization for long-term in vivo imaging. The PL spectrum showed typical Cr3+ emission due to 2E→4A2 and 4T2→4A2 transitions. The integrated PL intensity of Cr3+ luminescence (2E→4A2 plus 4T2→4A2 transitions) does not suffer from temperature quenching up to 600 K. From the TSL glow curve measurements, it was found that the persistent luminescence cannot be activated by visible light excitation. However, photostimulation induced persistent luminescence by red to near-infrared light can be possible in this material.