Abstract
In contrast to Yb3+ which is a well‐investigated optically active ion, the spectroscopic properties of its divalent counterpart Yb2+ in glasses are hardly investigated, although Yb2+ might have a notable influence on the luminescence properties of Yb3+‐doped glasses even at low Yb2+ concentrations because of its strong f‐d transitions. In this paper, we report on the preparation and spectroscopic properties of Yb2+‐doped aluminosilicate glasses that were produced using the normal melt‐quench technique. The glass composition is 20CaO·20Al2O3·60SiO2 (mol%). To achieve a sufficient amount of Yb2+ in the samples, different methods were applied to influence the red‐ox equilibrium during glass melting: firstly, under argon atmosphere and additional argon bubbling, and secondly by the addition of metallic aluminum powder to the batch. The strongly reduced samples show a greenish to brownish yellow coloring which could be attributed to the strong absorption of Yb2+ ions in the UV to blue spectral range. The absolute Yb2+ concentration in the glass and the molar extinction coefficient of Yb2+ was obtained by spectroscopic measurements. If irradiated with UV light, the Yb2+‐doped samples show a broad fluorescence emission in the wavelength range from 450 to 700 nm with a peak at around 515 nm.