Vanadium-doped MgAl2O4 crystals as white light source

Spinel MgAl2O4 crystals doped with transition metals show charge-transfer transitions for Ti:MgAl2O4 on one hand and multiplet transitions of (3d)-electrons for Mn:, Fe:, and Co:MgAl2O4 on the other hand. We will show that optical responses of V:MgAl2O4 are closer to those of Ti:MgAl2O4 and also that white emission spectrum is observed. The microscopic process of the white emission is also proposed.