Pr³+-doped YPO₄ nanocrystal embedded into an optical fiber

Abstract

Optical fiber with YPO₄:Pr³+ nanocrystals (NCs) is presented for the first time using the glass powder—NCs doping method. The method’s advantage is separate preparation of NCs and glass to preserve luminescent and optical properties of NCs once they are incorporated into optical fiber. The YPO₄:Pr³+ nanocrystals were synthesized by the co-precipitation and hydrothermal methods, optimized for size (< 100 nm), shape, Pr³+ ions concentration (0.2 mol%), and emission lifetime. The core glass was selected from the non-silica P₂O₅-containing system with refractive index (n = 1.788) close to the NCs (no = 1.657, ne = 1.838). Optical fiber was drawn by modified powder-in-tube method after pre-sintering of glass powder—YPO₄:Pr³+ (wt 3%) mixture to form optical fiber preform. Luminescent properties of YPO₄:Pr³+ and optical fiber showed their excellent agreement, including sharp Pr³+ emission at 600 nm (¹D₂–³H₄) and ¹D₂ level lifetime (τ = 156 ± 5 µs) under 488 nm excitation. The distribution of the YPO₄:Pr³+ NCs in optical fiber were analyzed by TEM-EDS in the core region (FIB-SEM-prepared). The successful usage of glass powder—NCs doping method was discussed in the aspect of promising properties of the first YPO₄:Pr³+ doped optical fiber as a new way to develop active materials for lasing applications, among others.