Hyperbolic materials exhibit unique properties that enable intriguing applications in nanophotonics. The topological insulator Bi₂Se₃ represents a natural hyperbolic optical medium, both in the THz and visible range. Here, using cathodoluminescence spectroscopy and electron energy-loss spectroscopy, we demonstrate that Bi₂Se₃ supports room-temperature exciton polaritons and explore the behavior of hyperbolic edge exciton polaritons, which are hybrid modes resulting from the coupling of the polaritons bound to the upper and lower edges of Bi₂Se₃ nanoplatelets. We compare Fabry-Pérot-like resonances emerging in edge polariton propagation along pristine and artificially structured edges and experimentally demonstrate the possibility to steer edge polaritons by means of grooves and nanocavities. The observed scattering of edge polaritons by defect structures is found to be in good agreement with finite-difference time-domain simulations. Our findings reveal the extraordinary capability of hyperbolic polariton propagation to cope with the presence of defects, providing an excellent basis for applications such as nanooptical circuitry, nanoscale cloaking and nanoscopic quantum technology.

双曲线材料具有独特的性能，可以在纳米光子学中引起人们的兴趣。拓扑绝缘体Bi ₂ Se ₃代表天然的双曲光学介质，在THz和可见光范围内。在这里，使用阴极发光光谱和电子能量损失光谱，我们证明Bi ₂ Se ₃支持室温激子极化子，并探索了双曲边缘激子极化子的行为，这是由于极化子结合到上部而产生的混合模式和Bi ₂ Se _3的下边缘纳米血小板。我们比较沿原始和人工构造的边缘在边缘极化子传播中出现的法布里-佩罗特样共振，并通过实验证明了通过凹槽和纳米腔来引导边缘极化子的可能性。发现由缺陷结构观察到的边缘极化子的散射与时域有限差分模拟非常吻合。我们的发现揭示了双曲极化子传播的非凡能力来应对缺陷的存在，为诸如纳米光学电路，纳米尺度的隐身术和纳米级量子技术等应用提供了极好的基础。