title: UV/blue upconversion in Nd3+:TeO2 glass, effect of modifiers and heat treatment on the fluorescence bands.
abstract: Upconversion (UC) emissions in UV/blue region have been observed in Nd(3+) doped tellurite glass on 532 nm excitation. The UC bands have been observed at 360, 387, 417 and 452 nm due to the (4)D(3/2)-->(4)I(9/2), (4)D(3/2)-->(4)I(11/2), (4)D(3/2)-->(4)I(13/2) and (4)D(3/2)-->(4)I(15/2) transitions, respectively and they show two photon character. The effect of BaCO(3), BaF(2) and BaCl(2) glass modifiers on the UC efficiency has been studied and Judd-Ofelt intensity parameters have been calculated and compared. The BaCl(2) modified glass showed maximum UC intensity among the three modifiers and this enhancement in UC intensity has been related to the reduction in average phonon frequency of the glass sample. Heat treatments of the BaF(2) and BaCl(2) modified samples also show enhancement in UC intensity while the BaCO(3) modified sample has no such effect. Lifetime of the (4)D(3/2) level has been measured to understand the mechanism responsible for UC emission. Temperature dependent fluorescence studies have been done on the (4)F(3/2), (4)F(5/2) and (2)S(3/2) emitting levels and results show that Nd(3+) doped tellurite glass can be used as a temperature sensor.
authors.affiliation: Laser Spectroscopy Laboratory, Department of Physics, Banaras Hindu University, Varanasi 221005, India.
authors.forename: R K
authors.initials: RK
authors.lastname: Verma
authors.forename: K
authors.initials: K
authors.lastname: Kumar
authors.forename: S B
authors.initials: SB
authors.lastname: Rai
mesh_terms: D006358:Hot Temperature; D008163:Luminescent Measurements; D009354:Neodymium / Q000737:chemistry*; D055095:Optics and Photonics; D013050:Spectrometry, Fluorescence; D013691:Tellurium / Q000737:chemistry*
chemical_list: D009354:Neodymium; C026660:tellurous acid; D013691:Tellurium