Conversion of two-micron radiation into visible light using glass and ceramics based on ZBLAN: Но3+ and ZBLAN: Ho3+ + Yb3+

Abstract

Visualization of infrared radiation of Tm:YLF-laser at the wavelength of 1908 nm has been investigated in the glass and ceramics samples with compositions of 53ZrF₄ · 20 BaF₂ · 1HoF₃ · 3YbF₃ · 3AlF₃ · 20NaF and 53ZrF₄ · 20BaF₂ · 3LaF₃ · 1HoF₃ · 3AlF₃ · 20NaF (mol %). In luminescence spectra of ZBLAN samples doped with Но³⁺, the bands at the wavelengths of 480, 540, and 650 nm were observed, which correspond to ⁵F₃ → ⁵I₈, ⁵S₂, ⁵F₄ → ⁵I₈, and ⁵F₅ → ⁵I₈ electron transitions in Но³⁺ ions with the maximum intensity of the red band (650 nm). Occupancy of the ⁵S₂ and ⁵F₄ levels in the ZBLAN: 1% Но³⁺ samples is related to the sequential absorption of the exciting radiation quanta. The level of ⁵F₅ is filled mainly due to the ionic interaction. Additional doping with the Yb³⁺ ions led to the change of the luminescence color to green and a decrease in the threshold radiation power density of the Tm:YLF-laser in ceramic samples up to 2 W/cm².