Abstract The 1.54 μm emission of Er3+ ions embedded in a dichroic Cu nanocomposite glass is shown to be either quenched or enhanced depending on the excitation wavelength. The synthesized material consisted of an aluminphosphate matrix co-doped with Cu and Er as prepared by thermal processing, and characterized by optical absorption and photoluminescence (PL) spectroscopy including an assessment of decay dynamics. The extinction spectrum presented a broad surface plasmon resonance (SPR) band for Cu nanoparticles (NPs) around 588 nm, while the glass appeared to scatter red light but transmit blue, i.e. exhibiting dichroism. Interestingly, the PL obtained for the 4I13/2 → 4I15/2 emission around 1.54 μm was enhanced under the excitation of the 4I15/2 → 4F9/2 transition at 650 nm, which turned out to be located toward the low energy wing of the SPR of Cu NPs. About a 12% PL boost was estimated relative to a merely Er3+-doped reference. Conversely, a PL quenching effect was manifested for resonant Er3+ excitations (e.g. 4I15/2 → 2H11/2 transition at 520 nm) overlaid with the 3d → 4sp interband transitions absorption in copper. It is suggested that favorable conditions for the PL enhancement are achieved for when the excitation of Er3+ ions can benefit from light scattering by plasmonic Cu particles, while an excitation energy transfer from Er3+ to Cu NPs via interband transitions leads to the quenching.

中文翻译：

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二色性铜纳米复合玻璃中 Er3+ 离子 1.54 μm 发射的激发依赖性增强和淬灭

摘要 嵌入二色性 Cu 纳米复合玻璃中的 Er3+ 离子的 1.54 μm 发射显示出根据激发波长被淬灭或增强。合成材料由通过热处理制备的共掺杂 Cu 和 Er 的磷酸铝基体组成，并通过光吸收和光致发光 (PL) 光谱表征，包括衰减动力学评估。消光光谱在 588 nm 附近为 Cu 纳米粒子 (NP) 提供了宽的表面等离子体共振 (SPR) 带，而玻璃似乎散射红光但透射蓝色，即表现出二色性。有趣的是，在 650 nm 处 4I15/2 → 4F9/2 跃迁的激发下，1.54 μm 附近的 4I13/2 → 4I15/2 发射获得的 PL 增强，结果证明它位于Cu NPs SPR的低能量翼。相对于仅掺杂 Er3+ 的参考，估计大约 12% 的 PL 提升。相反，共振 Er3+ 激发（例如 520 nm 处的 4I15/2 → 2H11/2 跃迁）与铜中的 3d → 4sp 带间跃迁吸收重叠，显示出 PL 淬灭效应。这表明当 Er3+ 离子的激发可以受益于等离子体 Cu 粒子的光散射时，可以获得 PL 增强的有利条件，而通过带间跃迁从 Er3+ 到 Cu NPs 的激发能量转移导致淬灭。4I15/2 → 520 nm 处的 2H11/2 跃迁）与铜中的 3d → 4sp 带间跃迁吸收重叠。这表明当 Er3+ 离子的激发可以受益于等离子体 Cu 粒子的光散射时，可以获得 PL 增强的有利条件，而通过带间跃迁从 Er3+ 到 Cu NPs 的激发能量转移导致淬灭。4I15/2 → 520 nm 处的 2H11/2 跃迁）与铜中的 3d → 4sp 带间跃迁吸收重叠。这表明当 Er3+ 离子的激发可以受益于等离子体 Cu 粒子的光散射时，可以获得 PL 增强的有利条件，而通过带间跃迁从 Er3+ 到 Cu NPs 的激发能量转移导致淬灭。