Determination of cross-relaxation efficiency based on spectroscopy in thulium-doped rare-earth sesquioxides. Issue 7 (1st April 2023)

• Record Type: Journal Article
• Authors: Zheng, Liwen; Wu, Hao; Zhang, Liangliang; Luo, Yongshi; Pan, Guo-Hui; Wang, Xiao-Jun; Hao, Zhendong; Zhang, Jiahua
• Is Part Of: Ceramics international. Volume 49:Issue 7(2023)
• Page Start: 11060
• Page End: 11066
• Publication Date: 2023-04-01
• Subjects: Tm3+ doped sesquioxides -- Cross-relaxation -- Quantum efficiency; Ceramics -- Periodicals; Céramique industrielle -- Périodiques; Ceramics; Periodicals; Electronic journals; 666
• DOI: 10.1016/j.ceramint.2022.11.301
• Languages: English
• ISSNs: 0272-8842

Abstract

Abstract: Tm 3+ doped cubic rare-earth sesquioxides have been recognized as excellent laser materials operating at ∼ 2 μm. Upon 3 H4 excitation by commercially available laser diode around 800 nm, a cross-relaxation (CR) process enables efficient Tm 3+ laser originated from 3 F4 → 3 H6 transition. The CR process, (Tm1: 3 H4, Tm2: 3 H6 ) → (Tm1: 3 F4, Tm2: 3 F4 ), cuts one excitation photon into two photons of 2 μm with quantum efficiency of 200%. As a result, efficient CR is needed. The CR efficiency is usually determined based on the emission lifetime of 3 H4 . However, the CR between the nearest Tm 3+ is too fast to emit, overrating the emission lifetime and underrating the CR efficiency. Here, we propose a spectroscopic method for determination of CR efficiency based on emission intensity ratio. Tm 3+ doped cubic Y2 O3, Lu2 O3, Sc2 O3, YScO3, LuScO3 and YLuO3 sesquioxides are prepared by solid-state reaction. Near infrared emission spectra and decay curves are studied as a function of Tm 3+ concentration. The relationship between CR efficiency and emission intensity ratio is established. Large Stark splittings of 1002 cm −1 and 511 cm −1 are observed for the 3 H6 ground state and the 3 F4 excited state of Tm 3+, respectively in Sc2 O3 :Tm 3+, leading to a long-wave emission at 2.15 μm. The comparison of these six samples reveals that Sc2 O3 : Tm 3+ has the largest CR parameter and Lu2 O3 :Tm 3+ has the highest quantum efficiency for populating the 3 F4 from the 3 H4 at the same Tm 3+ concentration.