Ag nanoparticles enhanced 2 um luminescences of Ho3+/Tm3+ codoped bismuth germanate glasses

Abstract

The Ho3+/Tm3+ codoped bismuth germanate glasses containing Ag nanoparticles (NPs) are synthesized by a chemical reduction method based on the conventional melting-quenching technique. The effect of concentration of Ag NPs on the 2 um emission is studied. The absorption band related to the surface plasmon resonance (SPR) of the Ag NPs is located in a range from 500 to 900 nm. Transmission electron microscopic image clearly reveals homogeneously dispersed Ag NPs with the sizes ranging from 5 to 10 nm. The luminescence spectra in a range of 1.7-2.3 um are collected. With the addition mass fraction of the AgCl up to 0.3%, the intensity of emission band of Ho3+ ions, centered at 2.03 um, is increased by 10 folds. The enhancement of 2 um luminescence is attributed to the enhanced local field induced by SPR of Ag NPs. The calculated absorption cross section and emission cross section are 0.491 10-20 cm-2 and 1.0310-20 cm-2, respectively. When the gain coefficient p=0.2, the positive gain would be realised.