title: Tuning of near-infrared-to-near-infrared luminescence from one-photon to two-photon anti-Stokes shift in Ca3Ga2-xCrxGe3O12via varying Cr3+content.
abstract: Near-infrared-to-near-infrared (NIR-to-NIR) anti-Stokes luminescence from Cr3+singly doped Ca3Ga2Ge3O12(CGGG) occurs under the excitation of an 808 nm diode laser. The anti-Stokes processes vary from one photon to two photon, depending on the Cr3+content (x) in Ca3Ga2-xCrxGe3O12. The results suggest that phonon-assisted anti-Stokes excitation and cooperative energy transfer are involved in the observed upconversion (UC) processes of CGGG:Cr3+. The relevant Cr3+-doping-concentration-dependent NIR-to-NIR anti-Stokes luminescent mechanism, either one-photon or two-photon UC, is investigated. Such an observation on modulating the UC process via varying the doping concentration is helpful in broadening the understanding of UC phenomena.
authors.forename: Huihong
authors.initials: H
authors.lastname: Lin
authors.forename: Ting
authors.initials: T
authors.lastname: Yu
authors.forename: Gongxun
authors.initials: G
authors.lastname: Bai
authors.forename: Qinyuan
authors.initials: Q
authors.lastname: Zhang
authors.forename: Jianhua
authors.initials: J
authors.lastname: Hao