Multi-photon UV upconversion luminescence of Yb³⁺ and Tm³⁺ co-doped ZBLAN glass

The ultraviolet upconversion luminescence properties of the Tm³⁺ ion sensitized by the Yb³⁺ ion were studied, in fluoride glass as excited by a 980 nm continuous wave diode laser. Red, blue, and even ultraviolet emissions were observed with ZrF₄-BaF₂-LaF₃- A1F₃-NaF glass, and it was also found that the peaks at 291, 347, 363, 454, 475, 643, 687 and 804 nm correspond to the transitions of ¹I₆→³H₆, ¹I₆→³F₄, ¹D₂→³H₆, ¹D₂→³F₄, ¹G₄→³H₆¹, G₄→³F₄, ³F₃→³H₆, and ³H₄→³H₆, respectively. According to the relationship between the pump power and the upconversion peaks intensity, 347 nm and 363 nm ultraviolet emissions are five photon and four photon processes respectively. The research results show that the ZrF₄-BaF₂-LaF₃-A1F₃-NaF glass of the Tm³⁺ ion sensitized by the Yb³⁺ ion can effectively transform the near-infrared waveband laser to the ultraviolet.