Photonic engineering of superbroadband near-infrared emission in nanoglass composites containing hybrid metal and dielectric nanocrystals

Abstract

Photonic media containing hybrid noble metal–dielectric nanocrystals (NCs) represent a wonderland of nanophotonics, with a myriad of uncharted optical functions yet to be explored. Capitalizing on the unique phase separation and spontaneous formation of Au-metal NCs in a gallosilicate glass, we fabricated Ni 2 + -doped transparent nanoglass composites (GCs) containing Au - metal / γ - Ga 2 O 3 -dielectric NCs. Compared with GCs free of Au-metal NCs, the superbroadband near-infrared emission of Ni 2 + with a full width at half-maximum over 280 nm is enhanced twice in the Au - metal / γ - Ga 2 O 3 dual-phase GCs. A comparison is given as to the spontaneous emission (SPE) properties of Ni 2 + in the dual-phase GCs when pumped resonantly and off-resonantly with the localized surface plasmon resonance band of the Au-metal NCs. The important role of the Au-metal NCs in the SPE enhancement is revealed by theoretical simulation based on the finite-element method. Combining the photonic engineering effect of hybrid Au - metal / γ - Ga 2 O 3 NCs and the sensitization effect of Yb 3 + on Ni 2 + , a record-high enhancement factor of over 10 of the Ni 2 + NIR emission is achieved, and optical gain is demonstrated in the GCs at the fiber communication wavelength.