Intense red upconversion luminescence from Tm³⁺/Yb³⁺ codoped transparent glass ceramic

Tm³⁺/Yb³⁺ codoped transparent glass ceramic containing β-PbF₂ nanocrystals was successfully prepared. After thermal treatment, emissions from the ¹G₄ state of Tm ³⁺ excited by 980 nm laser were greatly quenched by cross relaxation and the 700 nm luminescence from Tm³⁺:³F_2.3 →³H₆ transition was strongly enhanced. A nearly monochromatic red luminescence band was observed. Based on the luminescence decay curves and Judd-Ofelt analysis, the strengthened cross relaxation played an important role in such phenomenon.