INFLUENCE OF ALKALI-EARTH IONS ON 1.06 μm NEAR INFRARED EMISSION OF ND3+-DOPED LITHIUM ALUMINOPHOSPHATE GLASS FOR LASING APPLICATION

The influence of the alkali-earth ions (Mg²⁺, Ca²⁺, Sr²⁺) on structural (FTIR) and spectroscopic (optical absorption and near infrared emission) properties of Nd³⁺-doped lithium aluminophosphate glasses were systematically examined and discussed. Under an excitation wavelength of 580 nm, the emission spectra of Nd³⁺-doped glasses showed three prominent peaks at 900, 1058, and 1327 nm, it was related to the ⁴F_3/2 → ⁴I_9/2, ⁴I_11/2, and ⁴I_13/2 transitions, respectively. It was found that the peak emission intensity occurs at a wavelength of 1058 nm. The Ω₂, Ω₄ and Ω₆ were calculated by applying Judd-Ofelt theory to the absorption and emission measurements, which resulted in the radiative transition probability and stimulated emission cross-section being calculated. As a result, when compared to Ω₂, Ω₄, and Ω₆, have a larger compositional dependency on ionic radius and modifier content. In addition, it was found that the stimulated emission cross-section of σ_em(Sr)>σ_em(Ca)>σ_em(Mg), respectively. The luminescence intensity is greatly increased, and the underlying mechanism is clearly seen when cationic replacements of Sr²⁺, Ca²⁺, and Mg²⁺ are carried out. The research proved that spectroscopic properties of trivalent Nd³⁺ depend significantly on the kind of presence of alkali-earth ions in glass host matrices and could be used as a lasing application.