Tunable upconversion emission in NaLuF4–glass-ceramic fibers doped with Er3+ and Yb3

• Published in: RSC advances 2019-10, Vol.9 (54), p.31699-31707
• Main Authors: Gorni, G, Velázquez, Jose J, Kochanowicz, M, Dorosz, D, Balda, R, Fernández, J, Durán, A, Pascual, M J
• Format: Article
• Language: English
• Subjects: Ceramic fibers; Chemistry; Color; Control rods; Crystallization; Dependence; Emission; Energy transfer; Erbium; Excitation; Glass ceramics; Heat treatment; Nanocrystals; Optical fibers; Photonics; Upconversion; Ytterbium
• ISSN: 2046-2069; 2046-2069
• DOI: 10.1039/c9ra05182a

Novel glass-ceramic optical fibers containing NaLuF4 nanocrystals doped with 0.5ErF3 and 2YbF3 (mol%) have been prepared by the rod-in-tube method and controlled crystallization. NaLuF4 nanocrystals with a size around 20 nm are obtained after heat treatment at 600 °C. Intense upconverted green and red emissions due to (2H11/2, 4S3/2) → 4I15/2 and 4F9/2 → 4I15/2 transitions, respectively, together with a blue emission due to 2H9/2 → 4I15/2 transition have been observed under excitation at 980 nm. The intensity of the green and red upconversion bands shows a nearly linear dependence on the excitation power which can be explained by saturation effects in the intermediate energy states and proves that a sensitized energy transfer upconversion process is responsible for the population of the emitting levels of Er3+ ions. The upconversion emission color changes from yellow to green by increasing the excitation power density which allows to manipulate the color output of the Er3+ emission in the glass-ceramic fibers. The tunable emission color is easily detected with the naked eye. This interesting characteristic makes these glass-ceramic fibers promising materials for photonic applications.