Near-infrared luminescence enhancement in Yb3+/Ho3+ co-doped bismuth-tellurite glass by tailoring glass network
Feng Ren, Chunlai Song, Yuxuan Cong, Yuxiao Wu, Yuerong Bai, Dechun Zhou
Abstract
In this work, the glass network has been tailored by introducing the modifier WO 3 when a Ho 3+ /Yb 3+ co-doped bismuth-tellurite glass composition was designed. The physical, absorption, emission, structure, and gain characteristics of the glasses with the different contents of WO 3 were investigated comprehensively based on various tests and analytical methods such as absorption spectra , fluorescence spectra , Raman spectra , and J-O theory. The results show that both the optical band gap and the bridge oxygen content are enhanced remarkably while the substitution of TeO 2 by WO 3 , accelerating the transition from [TeO 3 ] to [TeO 4 ] units. Simultaneously, the value of Ω 6 reached the maximum of 2.26×10 -20 cm 2 when the WO 3 is equal to 10 mol%, indicating that the Stark splitting of Ho 3+ : 5 I 7 energy level is the weakest. The optimal FWHM and the gain coefficient are 143.3 nm and 2.22 cm -1 , respectively. Furthermore, a blue shift of the central wavelength in absorption and emission peaks can be observed at the 2 μm band. As mentioned above, the bismuth-tellurite glass prepared is an ideal gain material that can realize a wider spectra span.