Department of Nanomechanics, Tohoku University, Japan.
Sci Rep. 2016 Sep 13;6:33208. doi: 10.1038/srep33208.
We demonstrated fine emission wavelength tuning of quantum dot (QD) fluorescence by fine structural control of optical metamaterials with Fano resonance. An asymmetric-double-bar (ADB), which was composed of only two bars with slightly different bar lengths, was used to obtain Fano resonance in the optical region. By changing the short bar length of ADB structures with high dimensional accuracy in the order of 10 nm, resonant wavelengths of Fano resonance were controlled from 1296 to 1416 nm. Fluorescence of QDs embedded in a polymer layer on ADB metamaterials were modified due to coupling to Fano resonance and fine tuning from 1350 to 1376 nm was observed. Wavelength tuning of modified fluorescence was reproduced by analysis using absorption peaks of Fano resonance. Tuning range of modified fluorescence became narrow, which was interpreted by a simple Gaussian model and resulted from comparable FWHM in QD fluorescence and Fano resonant peaks. The results will help the design and fabrication of metamaterial devices with fluorophores such as light sources and biomarkers.
我们通过具有 Fano 共振的光学超材料的精细结构控制，展示了量子点 (QD) 荧光的精细发射波长调谐。非对称双棒 (ADB) 仅由两条长度略有不同的棒组成，用于在光学区域获得 Fano 共振。通过以 10nm 的高精度改变 ADB 结构的短棒长度，从 1296nm 到 1416nm 控制 Fano 共振的共振波长。由于与 Fano 共振的耦合以及从 1350nm 到 1376nm 的精细调谐，嵌入 ADB 超材料聚合物层中的 QD 荧光被修饰。通过使用 Fano 共振的吸收峰进行分析，再现了修饰后荧光的波长调谐。由于 QD 荧光和 Fano 共振峰的半峰全宽相当，因此修饰后荧光的调谐范围变窄。该结果将有助于设计和制造具有荧光团（如光源和生物标志物）的超材料器件。
