Yb3doped

Yb3+-doped materials are host lattices or glasses in which trivalent ytterbium ions (Yb3+) replace host cations to form active laser and amplifier media. The Yb3+ ion has a relatively simple two-manifold energy structure: a ground state 2F7/2 and the first excited manifold 2F5/2. Absorption bands near 900–970 nm enable direct pumping with common diode lasers, and emission centers around 1000–1100 nm allow efficient laser operation. The relatively small energy gap between the manifolds reduces nonradiative losses from excited-state absorption and upconversion, contributing to high quantum efficiency in many hosts.

Common hosts include crystalline materials such as YAG, YVO4, LuAG, and GGG, as well as phosphate, silicate and fluorophosphate glasses, and especially ytterbium-doped optical fibers. Doping levels vary: crystals typically 0.5–2 at% Yb; fiber compositions engineered to achieve high active ion density while maintaining optical quality. The strong absorption at ~930–970 nm and broad emission around 1030–1100 nm make Yb3+-doped media well suited to diode pumping and ultrafast amplification.

Performance depends on host phonon energy and temperature management. Nonradiative decay increases with high phonon energy hosts; consequently low-phonon hosts like YAG and LuAG offer high radiative efficiency. Fluorescence lifetimes range from hundreds of microseconds to about a millisecond depending on host and dopant level, enabling continuous-wave and pulsed operation, including mode-locked and chirped-pulse amplification in fibers.

Applications include solid-state lasers, fiber lasers and amplifiers, and optical frequency converters. Advantages include a relatively simple energy-level scheme, high quantum efficiency, and compatibility with diode pumping. Challenges include concentration quenching at high dopant levels and heat management in high-power operation.