title: Near vacuum ultraviolet luminescence of Gd3+ and Er3+ ions generated by super saturation upconversion processes.
abstract: Near vacuum ultraviolet (UV) upconversion (UC) emissions with a spectral resolution of 1 nm, from the (6)G(J), (6)D(J), (6)I(J), (6)P(J) levels of Gd(3+) and the (2)L(17/2), (4)D(7/2), (2)H(2)(9/2), (2)D(5/2), (4)G(7/2), (2)K(13/2), (2)P(3/2) levels of Er(3+), were observed under 974 nm laser excitation. Mechanism analyses illustrate that successive energy transfers (ETs) from Yb(3+) to Er(3+) generate UV UC radiations in Er(3+), while two resonant ETs from Er(3+) to Gd(3+) lead to UV UC radiations in Gd(3+). Power dependence analyses indicate that the expected inefficient four- and five-photon processes have been switched into efficient two-photon processes due to a super saturation UC phenomenon that employs consecutive saturations at the intermediate states.
authors.affiliation: Department of Physics, Harbin Institute of Technology, 150001 Harbin, People's Republic of China.
authors.forename: Guanying
authors.initials: G
authors.lastname: Chen
authors.forename: Huijuan
authors.initials: H
authors.lastname: Liang
authors.forename: Haichun
authors.initials: H
authors.lastname: Liu
authors.forename: Gabriel
authors.initials: G
authors.lastname: Somesfalean
authors.forename: Zhiguo
authors.initials: Z
authors.lastname: Zhang