Glasses for praseodymium laser amplifiers sensitised with neodymium and ytterbium

A new sensitised scheme for optical pumping of praseodymium amplifiers, operating in the spectral range 1.3 μm, was proposed and investigated. The amplifiers were pumped in the absorption band of neodymium ions. In fluoride glasses with a high ytterbium ion concentration, the excitation energy was efficiently nonradiatively transferred along the Nd³⁺ — Yb³⁺ — Pr³⁺ chain.