Visible red, NIR and Mid-IR emission studies of Ho3+ doped Zinc Alumino Bismuth Borate glasses

Abstract

Zinc Alumino Bismuth Borate (ZnAlBiB) glasses doped with different concentrations of Holmium were prepared by conventional melt quenching technique. The glassy nature of these glasses has been confirmed through the XRD spectral measurements. The FTIR spectra recorded for undoped glass revealed the information related to the functional groups involved in the host glass. Optical absorption, excitation and photoluminescence spectra of these glasses have been recorded at room temperature. The Judd–Ofelt theory has been applied successfully to characterize the absorption spectra of the ZnAlBiB glasses. From this theory various radiative properties such as radiative transition probability (AR), radiative lifetimes (τR), branching ratios (βR) and spectroscopic quality factor (χ) for the prominent emission levels 5F5→5I7, 5F5→5I8 and 5I7→5I8 have been evaluated. The photoluminescence spectra revealed the quenching of luminescence intensity beyond 1.0mol% of Ho3+ ion concentration in ZnAlBiB glasses. To investigate the lasing potentiality of 5F5→5I7, 5F5→5I8 and 5I7→5I8 transitions, the effective band width (Δλp) and the stimulated emission cross-section (σse) were determined. The CIE chromaticity co-ordinates were also evaluated from the emission spectra for all the glasses to understand the suitability of these materials for visible red laser emission in principle.