High-color-rendering white light and broadband optical gain of Ag-aggregates/Mn2+ co-doped germanate glasses

Ag-aggregates and Mn ²⁺ doped germanate glasses were prepared by a melt-quenching method, and their spectroscopic and chromatic properties were studied. It was found that Ag-aggregates doped samples exhibited broadband emission covering almost the visible spectral range. When Mn ²⁺ with ⁴T ₁( ⁴G) to ⁶A ₁( ⁶ S) transition was introduced, the broadband emission of Ag-aggregates doped germanate glass was further extended in red light range. Meanwhile, the luminescence color coordinate and correlated color temperature (CCT) of Ag-aggregates/Mn ²⁺ co-doped sample excited by 360 nm were derived to be (0.33, 0.32) and 5616.7 K, respectively, and its color rendering index (CRI) is up to 93. Moreover, the optical gain at various wavelengths was investigated based on an amplified spontaneous emission (ASE) technique, and the Ag-aggregates/Mn ²⁺ co-doped sample possesses broadband optical gain in full visible range. These results indicate that Ag-aggregates/Mn ²⁺ co-doped germanate glasses are promising candidates for applications in white light-emitting-diodes (wLEDs) and broadband tunable lasers.