Tm3+ doped Bi2O3-GeO2 glasses with silver nanoparticles for optical amplifiers in the short-wave-infrared-region

Abstract

We synthesized the Bi2O3–GeO2 (BGO) glass doped with thulium ions (Tm3+) and investigate the influence of embedded silver nanoparticles (Ag-NPs) on the samples photoluminescence (PL) and on the process of energy transfer (ET) among bismuth ions and Tm3+. The samples were prepared by the melt-quenching method with and without Tm2O3 and/or AgNO3. Under excitation at 808 nm the pure BGO glass presented PL from 1100 to 1500 nm, characteristic of the bismuth ions, Bi+, while the samples with Tm3+ exhibited a strong PL from 1300 to 1600 nm. The Bi+ emission was quenched due to ET from the bismuth centers to the Tm3+ and the emitted intensity at 1470 nm increased by more than 1000% due to the presence of Tm3+. Moreover, the samples with Tm3+ and Ag-NPs presented further PL enhancement of ≈56% at 1470 nm for the samples heat-treated during 2 h. Optical gain measurements using 2 mm thick samples were performed with a probe beam at 1470 nm and the pump beam at 808 nm. A 4.5 dB/cm gain in the presence of Ag-NPs was measured when the pump laser power was 6 W. The Ag-NPs contributed to 500% of gain enhancement. The present results illustrate the appropriateness of the BGO glass with Tm3+ and Ag-NPs for obtaining intense PL and optical amplification in the near-infrared.