Optical properties of rare earth ion (Nd3+, Er3+ and Tb3+)-doped alumina films prepared by the sol-gel method

Rare earth ion (Nd3+: Er3+ and Tb3+)-doped alumina films were prepared by t he sol-gel method using aqueous alumina sol. The effects of dopant concentr ation and treatment temperature on the optical properties, absorption and e mission were examined for the doped films. Alumina films prepared by this m ethod gave a high dopant concentration (0-15 mol% per alumina). Significant concentration quenching did not occur in this concentration range. The emi ssions from D-5(3) and D-5(4) Of Tb3+-doped film reflected sensitively a ma trix environment around Tb3+ ions. Er3+ and Nd3+-doped alumina films resona ntly excited by cw Ti-sapphire laser (800 nm) showed upconversion emission at room temperature. The former gave 548 nm (S-4(3/2) --> I-4(15/2)) and 64 0 nm (F-4(9/2) --> I-4(11/2)) signals, and the latter 640 nm ((4)G(7/2) --> I-4(1/2)), which were dependent on alumina. (C) 2001 Elsevier Science B.V. All rights reserved.