Optical properties of Sm3+ doped strontium bismuth borosilicate glasses for laser applications

Abstract

Stupendous progress in realizing optical materials is due to extreme strides which were adapted so far in understanding optical properties of materials. Keeping this in view a series of Bismuth Borosilicate glasses modified with strontium and doped with various concentrations of Sm3+ (SrOBi2O3B2O3SiO2Sm2O3) have been prepared by classical melt quench technique. These glasses were structurally characterized by XRD to confirm amorphous nature. Vibration mode analysis of samples has been analyzed by infrared transmission spectroscopy. This paper show cases various optical phenomena such as absorption and luminescence which plays a key role in design of engineered optical materials. To understand absorption, optical excitation, emission and time decay process optical spectroscopy measurements were done. Judd-Ofelt (JO) theory was employed to determine intensity parameters Ωλ=2,4,6 for symmetry of ligand environment existing among Sm3+ ions. From emission spectra various radiative parameters like transition probability (Ar), branching ratios (βr) and radiative time were determined. Emission bands of 4G5/2 → 6H5/2 (560 nm), 4G5/2 → 6H7/2 (599 nm) 4G5/2 → 6H9/2 (636 nm) and 4G5/2 → 6H11/2 (708 nm) have been recorded with excitation at 401 nm. Above all emission wavelengths 599 nm is more intense and has shown a bright orange emission. Among four emission bands corresponding to 4G5/2 → 6H7/2 transition in emission spectra shows high (σE) peak stimulated emission (22.85 × 10−22 cm2) and optical gain (O.G) is (28.33 × 10−25 cm2s) assure optoelectronic applications. The life time τ exp of excited level 4G5/2 was determined through decay and non-exponential decay curves. Inokuti-Hirayama model was used to fit non exponential curve for the analysis of luminescence quenching, quantum efficiency (96%), transfer mechanism of energy among Sm3+ ions to ensure Laser applications. CIE colour chromaticity coordinates of present Sm3+ doped glasses also suggest the synthesized glasses are suitable improvement of orange-red lasers.