The Investigation Of The Growth And Spectral Properties About Nd:Ca_xGd_1-xVO₄

It is that the emergence and fast development of the high power laser dioded provided terms for researching new laser crystals. This thesis gives a brief introduction of the latest research trend for laser crystals and the development progress of rare-earth laser crystals. Meanwhile, the possibility of Ca²⁺-doped Nd:GdVO₄ crystal used for self-Raman laser crystal was discussed. GdVO₄ crystal belongs to tetragonal system, with space group of D4h-I41/amd. According to the results of many experiments, a series of different Nd³⁺ ion-doped concentrations Nd:Ca_xGd_1-xVO₄ single crystals were grown by Czochralski method with technique parameters of 1.0².0mm/h pulling rate and 10 r.p.m. rotation rate. The Nd³⁺ ions concentrations in Ca_0.08Gd_0.92VO₄ crystal were obtained by ICP-AES method; the efficient distribution coefficient of Nd³⁺ in crystal was calculated as 0.71, which is favorable for Nd³⁺ high dopant. Chemical etching techniques were used to measure the dislocation density of as grown crystals; the result indicated that low pulling rate would reduce the dislocation density in Ca_xGd_1-xVO₄ crystal. The Raman spectra of Ca_xGd_1-xVO₄ were measured at room temperature, and all Raman peaks were assigned on the basis of the group theory. The influence of Ca²⁺ ion doped concentration on the Raman gain coefficient of Ca_xGd_1-xVO₄ crystal was discussed. Absorption and fluorescence spectra of Nd:Ca_0.08Gd_0.92VO₄ were measured at room temperature. The absorption cross section of 1.48at.at.% Nd:Ca_0.08Gd_0.92VO₄ crystal is 6.533×10^-20cm², FWHM was 13nm at 808nm, so Nd:Ca_0.08Gd_0.92VO₄ crystal is fit to be pumped by 808nm LD. Based on the Judd-Ofelt theory, the spectral parameters of Nd³⁺ ions in this crystal such as radiative lifetime Ï„_R and emission cross-section σ_em were calculated as 125.8 μs and 43.8×10^-20cm², respectively.