title: Efficient violet upconversion signal from a fluoride fiber doped with erbium.
abstract: When an erbium-doped fluoride fiber was pumped with a red dye laser beam that resonantly excites the (4)F(9/2) state, we detected efficient violet upconversion emission from the (2)P(3/2) state that is much stronger than the green upconversion emission from the (4)S(3/2) state. Such unusual violet emission was found to be due to a three-photon excitation process.
authors.forename: C L
authors.initials: CL
authors.lastname: Pope
authors.forename: B R
authors.initials: BR
authors.lastname: Reddy
authors.forename: S K
authors.initials: SK
authors.lastname: Nash-Stevenson