Investigation of Yb3+-doped alumino-silicate glasses for high energy class diode pumped solid state lasers

Abstract

We present a detailed investigation of different compositions of Yb3+-doped alumino-silicate glasses as promising materials for diode-pumped high-power laser applications at 1030 nm due to their beneficial thermo-mechanical properties. To generate comprehensive datasets for emission and absorption cross sections, the spectral properties of the materials were recorded at temperatures ranging from liquid nitrogen to room temperature. It was found that the newly developed materials offer higher emission cross sections at the center laser wavelength of 1030 nm than the so far used alternatives Yb:CaF2 and Yb:FP-glass. This results in a lower saturation fluence that offers the potential for higher laser extraction efficiency. Fluorescence lifetime quenching of first test samples was analyzed and attributed to the hydroxide (OH) concentration in the host material. Applying a sophisticated glass manufacturing process, OH concentrations could be lowered by up to two orders of magnitude, rising the lifetime and the quantum efficiency for samples doped with more than 6.1020 Yb3+ -ions per cm³. First laser experiments showed a broad tuning range of about 60 nm, which is superior to Yb:CaF2 and Yb:FP-glass in the same setup. Furthermore, measurements of the laser induced damage threshold (LIDT) for different coating techniques on doped substrates revealed the appropriateness of the materials for short pulse high-energy laser amplification.