Nd3+-Doped Lead Boro Selenate Glass: A New Efficient System for Near-Infrared 1.06 μm Laser Emission

Abstract

An exotic series of glasses with the composition 39PbO—(60–x)B2O3–xSeO2:1.0 Nd2O3 (10 ≤ x ≤ 50) is prepared and characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), and energy dispersive X-ray spectroscopy (EDS) techniques. Results of infrared (IR), Raman, and X-ray photoelectron spectroscopy (XPS) studies reveal that the glass network comprises quarantined selenite [SeO3]2− groups (that act as modifiers) and selenate [SeO4]2− groups in addition to BO3 and BO4 units. With the increase in SeO2 content, the concentration of selenite groups is found to be dominant. The optical absorption (OA) spectra exhibit several bands due to 4I9/2→2P1/2, 2G9/2, 4G9/2,7/2,5/2, 2H11/2, and 4F9/2, 7/2,5/2,3/2 transitions. The spectra are characterized using J–O theory and J–O parameters are found to follow the order: Ω2 > Ω6 > Ω4. The emission spectra recorded at λexc= 808 nm exhibit bands due to 4F3/2 → 4I9/2, 4I11/2, and 4I13/2 transitions. With increase in SeO2 content, intensity of all emission bands significantly increases. The quantum efficiency evaluated from the measured and calculated lifetimes of the 4F3/2 → 4I11/2 transition is found to be enhanced by 20% with increase in SeO2 from 10 to 50 mol%. The spectra are further analyzed quantitatively using kinetic rate equations of various excited levels and the reasons for enhancement of photoluminescence (PL) emission are identified and discussed.