Anti-Stokes Luminescence in LiYF4:Ho3+, Yb3+ Ceramics Excited at 1.93 μm

Abstract

Conversion of IR radiation of a Tm:YAP laser with a wavelength of 1930 nm into visible light by ceramics of composition LiY_(1–x–y) Ho_xYb_y, where х = 1–5 mol % and y = 0–15 mol %, is demonstrated. It is shown that the threshold power density of IR light visualization decreases with increasing concentration of Ho³⁺ ions, while additional doping of ceramic samples with Yb³⁺ ions changes the anti-Stokes luminescence spectrum. The threshold power density of visualization of the Tm:YAP laser radiation decreases with increasing concentration of holmium ions and is I_thr ≈ 0.8 W cm^–2 in the samples of composition LiYF₄:5%Ho³⁺–15%Yb³⁺.