Emission features of Er3+ ions in an exotic SeO2 based glass system

Abstract In this work we have studied impact of SeO2 concentration on luminescence properties of 39PbO-(60-x)B2O3-xSeO2:1.0 Er2O3 ( 10 ≤ x ≤ 50) glass system. The structural analysis of the samples carried out by XRD, SEM indicated that the prepared samples are in amorphous phase. IR, Raman and XPS studies revealed increasing presence of isolated selenite [SeO3]2−groups and decreasing concentration of [SeO4]2−(selenate) groups with increasing content of SeO2 in the glass network. Optical absorption (OA) spectra revealed absorption bands due to 4I15/2 → 4F7/2, 9/2, 2H11/2, 4S3/2, 4I9/2, 11/2, 13/2 transitions of Er3+ ions. Using J-O theory, the spectra were characterized and the evaluated Ωλ parameters are found to be in the order: Ω2 > Ω4 > Ω6. The PL spectra recorded at λexc= 378 nm exhibited the emission bands due to 2H11/2→4I15/2 (B), S3/2→4I15/2(G), 4F9/2→4I15/2(O) and 4I13/2→4I15/2 (NIR) transitionsof Er3+ ions. With the gradual increase SeO2 content, the PL emission bands (especially green and NIR bands) have exhibited significant growth. The spectra were quantitatively analysed using kinetic rate equations and the causes for enhancement of PL emission were recognised and discussed. From the gain co-efficient G(λ) of the 4I13/2→4I15/2 transition, its lasing behaviour is detected for a population inversion of nearly 50%.