Tunable ytterbium lasers

Trivalent ytterbium has been shown to have favorable properties over trivalent neodymium as a 1 μm laser source when pumped at 940 or 968 nanometers. These properties include a broader absorption band, a longer fluorescence lifetime and smaller photon decrement between the pump beam and the Yb³⁺ laser emission. An additional feature of the ytterbium ion is a broader fluorescence linewidth (compared to Nd ³⁺:YAG) which allows for tunable performance and flexibility in the selection of an output wavelength. The simple energy level scheme of Yb³⁺ makes it useful for resonant pumping without the inherent problems of excited state absorption and upconversion processes. In the paper the authors report on the performance of Yb:YAG and Yb:GSGG with CW pumping