In this work, the impact of metallic and dielectric conducting substrates, gold and indium tin oxide (ITO)-coated glass, on the whispering gallery modes (WGMs) of semiconductor π-conjugated polymer microspheres is investigated. Hyperspectral mapping was performed to obtain the excitation-position-dependent emission spectra of the microspheres. Substrate-dependent quenching of WGMs sensitive to mode polarization was observed and explained. On a glass substrate, both transverse-electric (TE) and transverse-magnetic (TM) WGMs are quenched due to frustrated total internal reflection. On a gold substrate, however, only the TM WGMs are allowed in symmetry to leak into surface plasmons. An atomically flat gold substrate with subwavelength slits was used to experimentally verify the leakage of WGMs into the surface plasmon polaritons (SPPs). This work provides insight into the damping mechanisms of WGMs in microspheres on metallic and dielectric substrates.

中文翻译：

---

等离激元和介电基底对自组装荧光半导体聚合物微球中回音壁模式的影响

在这项工作中，研究了金属和介电导电基底、金和氧化铟锡 (ITO) 涂层玻璃对半导体 π 共轭聚合物微球回音壁模式 (WGM) 的影响。进行高光谱映射以获得微球的激发位置依赖性发射光谱。观察并解释了对模式偏振敏感的 WGM 的基底依赖性猝灭。在玻璃基板上，横向电 (TE) 和横向磁 (TM) WGM 均因全内反射受抑而被淬灭。然而，在金基底上，仅允许 TM WGM 对称地泄漏到表面等离子体激元中。使用具有亚波长狭缝的原子级平坦金基板来通过实验验证 WGM 泄漏到表面等离子体激元 (SPP) 中。这项工作深入了解了金属和介电基板上微球中 WGM 的阻尼机制。