Studies of radiative and mechanical properties of Nd3+-doped lead fluorosilicate glasses for broadband amplification in a chirped pulse amplification based high power laser system

Abstract

Lead fluorosilicate (SPbKNLFNd: SiO2 + PbF2 + K2O + Na2O + LiF + Nd2O3) glasses doped with different concentrations of Nd3+ ions have been prepared by the melt quenching technique and characterized the compositional, mechanical and spectroscopic properties. The elements present in the chemical composition of lead fluorosilicate glass were analyzed by X-ray fluorescence spectra (XRF). The structural analysis and OH- content has been evaluated from FTIR spectra. Judd–Ofelt (JO) theory has been applied to the absorption spectrum of 1.0mol% Nd3+-doped lead fluorosilicate glass to estimate the JO intensity parameters (Ωλ, λ=2, 4 and 6) which are in turn used to calculate the radiative properties of luminescent level of Nd3+ ions. The near infrared emission spectra recorded with 808nm laser diode excitation for different concentrations of Nd3+ ions show that the emission intensity is highest for the 4F3/2→4I11/2 transition at 1056nm. The measured decay times for the 4F3/2 level decreased with increasing Nd3+ ions concentration due to the concentration quenching. The laser parameters such as stimulated emission cross-section (σe =4.11×10–2°cm2) and Vickers's hardness (3.59GPa) were found to be higher for the 1.0mol% of Nd3+:SPbKNLF glass along with wider fluorescence bandwidth (∆λeff ~ 36nm) at ∆λp ~ 1056nm. The obtained values are strong evidence that the SPbKNLFNd glasses could be useful for broadband amplification in a chirped pulse amplification (CPA) based high power laser systems. The results obtained in the present study have been compared with similar results obtained for Nd3+:glasses.