OPTICAL PROPERTIES OF ALKALI- AND ALKALINE-EARTH LEAD BORATE GLASSES DOPED WITH Nd~(3+) IONS

摘要

Spectroscopic and physical properties of Nd~(3+) doped alkali lead borate glasses of type 20R2O·30PbO·49.5B2O3·0.5Nd2O3 (R=Li and K), and alkaline-earth lead borate glasses 20RO·30PbO·49.5B2O3·0.5Nd2O3 (R = Ga, Ba and Pb) have been investigated. Optical absorption spectra have been used to determine the Slater-Condon (F2 , F4, and F6), spin orbit ξ_(4f) and Racah parameters (E1, E2, and E3). The oscillator strengths and the intensity parameters Ω2, Ω4 and Ω6 have been determined by the Judd-Ofelt theory, which in turn provide the radiative transition probability (A), total transition probability (A_T), radiative lifetime (τ_R) and branching ratio (β_R, %) for the fluorescent levels. The lasing efficiency of the prepared glasses has been characterized by the spectroscopic quality factor (Ω4/Ω6), the value of which is in the range of 0.2-1.5, typical for Nd~(3+) in different laser hosts. A red shift of the peak wavelength is observed upon addition of alkali-earth or alkaline oxides to the lead borate glass. A higher value of the Ω2 parameter for potassium-doped glass indicates a higher covalency for this glass matrix. The relative intensity of the peaks 4I_(9/2)→~4F_(7/2), ~4S_(3/2), has also been studied.