The study on BWGd:Nd glass for new laser amplifier: Properties, theoretical and practical investigations

The new laser-amplifier glass, Nd3+ doped tungsten gadolinium borate glass (BWGd:Nd), was investigated in this work. Glasses with different Nd2O3 concentration were prepared by melt-quenching technique. The measured density, refractive index and other calculated physical parameters leaded to the assumption that the degree of Nd-O covalency and the number of NBO increased with addition of Nd2O3 content. The enhancement of both factors possibly increased the strength of ligand field that slightly shifted and split some energy levels of Nd3+. The energy level splitting from 4F5/2 state was an intermediate level which accelerated the Nd3+ population on the 4F3/2 luminescence level by single-phonon relaxation. This electron-phonon coupling and low phonon energy of BWGd host glass was a key for strong Nd3+ luminescence of 4F3/2 -> 4I11/2 transition (1074 nm) and high radiative parameters, especially the high quantum efficiency around 96%. Due to high value of Delta lambda eff as well as sigma em but no long Texp value, this glass is suitable for laser amplifier. In practical laser-amplifier experiment, the gain amplification of developed glass was around 1.5 times under pumping power of 3.55 W. The BWGd:Nd glass performed high ability and may using as laser-amplifier material in the laser fusion and other applied laser system.

Automated summary

This study investigated a new laser-amplifier glass, Nd3+ doped tungsten gadolinium borate glass (BWGd:Nd). The addition of Nd2O3 content increased the degree of Nd-O covalency and the number of NBO, leading to the enhancement of the ligand field strength and the splitting of Nd3+ energy levels. The strong Nd3+ luminescence was achieved through electron-phonon coupling and low phonon energy. In practical experiments, the developed glass demonstrated high gain amplification under pumping power of 3.55 W.