title: Red to green upconversion in Er(3+)-doped BaTiO3 nanorods.
abstract: We investigated the frequency upconversion (UC) process in BaTiO3:Er3+ nanocrystals for excitation wavelengths in the range 638 to 660 nm. Green upconversion emissions at 526 and 547 nm corresponding to 2H11/2 --> 4I15/2 and 4S3/2 --> 4I15/2 to transitions of the Er3+ were observed. The excitation spectrum for UC emissions presented three bands, due to ground state and excited state absorption of Er3+ ions. The UC intensity as a function of the laser power was investigated and it was found this a two-photon absorption process.
authors.affiliation: Departamento de Física, Universidade Federal de Alagoas, 57072-970, Maceió, AL, Brazil.
authors.forename: Márcio A R C
authors.initials: MA
authors.lastname: Alencar
authors.forename: Glauco S
authors.initials: GS
authors.lastname: Maciel
authors.forename: Cid B
authors.initials: CB
authors.lastname: de Araújo
authors.forename: Amitava
authors.initials: A
authors.lastname: Patra