High-efficiency ∼2 µm CW laser operation of LD-pumped Tm3+:CaF2 single-crystal fibers

Yangxiao Wang; Shaozhao Wang; Jingya Wang; Zhonghan Zhang; Zhen Zhang; Rongrong Liu; Yuqian Zu; Jie Liu; Liangbi Su

doi:10.1364/OE.386659

High-efficiency ∼2 µm CW laser operation of LD-pumped Tm³⁺:CaF₂ single-crystal fibers

Opt Express. 2020 Mar 2;28(5):6684-6695. doi: 10.1364/OE.386659.

Authors

Yangxiao Wang, Shaozhao Wang, Jingya Wang, Zhonghan Zhang, Zhen Zhang, Rongrong Liu, Yuqian Zu, Jie Liu, Liangbi Su

PMID: 32225910
DOI: 10.1364/OE.386659

Abstract

The Tm:CaF₂ single-crystal fibers were successfully grown by modified temperature gradient technique method. The J-O intensity parameters, spontaneous radiative transition rates, radiative lifetimes and fluorescence branching ratios of Tm³⁺ were calculated with Judd-Ofelt theory. A systematic study of the fluorescence characteristics has been carried out. Simulated emission cross-sections of the ³F₄ → ³H₆ transition were calculated to be 6.68×10^-21 cm^-2 and 4.65×10^-21cm^-2 for crystal doped with 3 at.% and 4 at.% Tm³⁺. The 64.4% slope efficiency with output power of 2.23W was achieved in 3 at.% Tm:CaF₂ single-crystal fiber. The slope efficiency decreased to 44.5% and maximum output power decreased to 1.65W in 4 at.% Tm:CaF₂ single-crystal fiber. Obtained results show that Tm-doped CaF₂ single-crystal fibers are promising materials for IR laser action generation.