Continuous tuning of optical transition properties and phonon spectrum in Er3+ doped germano-tellurite glass system

Abstract

With the development of science and the progress of technology, novel and advanced rare earth ions doped luminescent materials with higher performance are demanded in the both emerging and traditional applications. Understanding the rules for tuning the spectroscopic properties of these materials is crucial for their development. However, achieving precise control over the optical properties of rare earth doped materials using traditional design and synthesis methods, such as altering dopants and their concentrations or modifying the preparative conditions, still remains challenging. This work aims to adjust the optical transition characteristics of Er3+ doped germano-tellurite glasses by changing the glass components. First, the Er3+ doped germano-tellurite glass series were synthesized using a high-temperature melt-quenching method at optimized melting temperatures. The tuning of band gap energy and refractive index of the glasses were revealed, and it was found that both of them can be monotonically and continuously tuned by changing the glass composition. The optical transition intensity parameters of Er3+ in the glasses were calculated in the framework of traditional three-parameterized Judd-Ofelt theory using the absorption spectra, and furthermore the corresponding optical transition parameters including radiative transition rates and intrinsic lifetimes for some interested levels were alsoconfirmed. The results demonstrated that the optical transition parameters could be efficiently modulated by changing the glass composition, indicating that the spectral properties of Er3+ doped germano-tellurite glasses can be tuned for the practical applications. The reliability of the deduced tuning rule was validated by comparing the theoretical and experimental transition rate ratios of 2H11/2 → 4I15/2 to 4S3/2 → 4I15/2. Furthermore, the tuning regulation of the phonon spectra in relation to the glass composition was discovered, showing a concordance between theoretical predictions and experimental results. From the above facts, it can be concluded that the optical transition properties of Er3+ in germano-tellurite glasses can be substantially adjusted by modifying the glass composition. This work provides a new perspective for designing and developing novel luminescent materials to meet specific application needs.