Evaluation of the most suitable new glass laser medium to incorporate Ytterbium

Abstract

The most important advantage of Ytterbium compared to others dopants such as Neodymium is its broadband emission nature, which is very suitable for both tunable and ultrafast lasers. In this paper we present the study and characterization of three different glass families: Alkali Niobium Tellurite, Lead Fluoroborate and of Heavy Metal Oxides, all prepared containing Ytterbium. The Ytterbium (Yb) emission spectrum in Tellurite glass samples was obtained by excitation into the absorption peak at 975 nm. The Yb peak emission cross-section was calculated using the fluorescence lineshape, the radiative lifetime (0.59 ms) and the refractive index 2.09. With these values we found the emission cross-section of Yb in Tellurite glass doped. Lead Fluorborate glasses have high refractive index of 2.2, and an absorption band centered at 968nm. The spontaneous emission probability was calculated and we determined that it decreases with the increase of Yb concentration. The same applies for the fluorescence lifetime and to the emission cross-section. We measured the fluorescence lifetime of 0.81ms, and an emission band at 1022nm with an effective emission linewidth of 60nm. Heavy metal oxide glass also has high refractive index (2.5) and transmission cutoff of about 8mm. In this glass the fluorescence effective linewidth was 86nm and radiative lifetime 300 ms. Calculations of the minimum pump intensity are also presented. A comparison of laser properties of these three different glasses and their importance is shown and analyzed.