Spectroscopy and excited-state absorption of Ni2+-doped MgAl2O4

Luminescence, ground-state and excited-state absorption and lifetime measurements on Ni2+-doped MgAl2O4 were performed. Excited-state absorption bands at 1700 nm in the near infrared and at 750 and 580 nm in the visible region due to the transitions from the 3T2 (3F) metastable state to the 3T1(3F), 1T2(1D), and 3T1(3P) states were observed and ESA cross sections were determined. The 3T2-3T1(3F) ESA band overlaps with the emission band and prevents lasing of Ni2+ : MgAl2O4 at room temperature.