标题： 非共振下通过间接光学跃迁增强折射率 显示英文标题

标题： Off-Resonance Enhancement of the Refractive Index via Indirect Optical Transitions

摘要： 在共振时，均匀介质对入射光的光学响应由时间色散支配，这会引起折射率（RI）的变化。 然而，最近的实验结果揭示了在空间受限系统中RI增强超过5的基本极限。 在此，我们研究使用电子光散射（ELS）在亚5纳米金纳米颗粒中RI的非共振增强。 我们讨论了由激发态电荷载流子的分布和动力学驱动的RI可以通过物质中空间对称性的破坏而局部增强。 这些发现对于使用ELS在空间受限介质中光学探测RI变化至关重要。 显示英文摘要

摘要： At resonance, the optical response of a homogeneous medium to incident light is governed by temporal dispersion, which induces changes in the refractive index (RI). However, recent experimental results reveal RI enhancements exceeding the fundamental limit of 5 in spatially confined systems. Herein, we study the off-resonance enhancement of RI in sub-5 nm gold nanoparticles using electronic light scattering (ELS). We discuss that the RI driven by the distribution and dynamics of excited-state charge-carriers can be locally boosted through the breaking of spatial symmetry in matter. These findings are critical for optically probing RI variations in spatially confined media using ELS.