AI 中文总结
该研究通过使用亚表面散射体，将单晶α-MoO3中高阶双曲声子极化激元的激发效率提升10倍，结合数值模拟与转移矩阵法，实现了对该类极化激元激发的确定性调控，推进了其在片上复用的应用能力。
AI 中文摘要
双曲材料具有极端形式的双折射特性，可实现深亚衍射光学模式的体积限制与频率相关传播，通过激发极化激元模式提供了极端限制的机会，高效激发其支持的高阶（更短波长）双曲极化激元模式可获得显著更高的限制效果。然而，尽管这些高阶双曲极化激元（HO-HPhPs）在体内形成高动量类射线传播，但与长波长低动量表面极化激元传播模式相比，这些模式的高效激发仍然是一个挑战。关键在于，这些模式与自由空间光之间存在大的动量失配，以及亚衍射散射体与HO-HPhPs的不同模式分布之间的空间失配，导致高阶模式的激发效率被抑制，限制了它们在纳米光子学应用中的使用。在此，我们报告在单晶α-MoO3薄片中，通过使用亚表面散射体（如薄片边缘或金发射器等传统表面散射体），HO-HPhPs的激发效率提高了10倍的实验观察结果。我们采用全波数值模拟研究了HO-HPhP模式分布与散射体位置之间的空间重叠对激发效率的作用。此外，我们开发了一种使用转移矩阵法的通用流程，用于选择性设计HO-HPhP的激发，这推进了片上应用中HPhP复用的能力。
英文摘要
Hyperbolic materials, which exhibit an extreme form of birefringence enabling the volume confinement and frequency-dependent propagation of deeply sub-diffractional optical modes, offer the opportunity for extreme confinement via the stimulation polaritonic modes, with substantially higher confinement obtained through the efficient excitation of of the higher-order (shorter wavelength) hyperbolic polaritonic modes, which they can support. However, while these higher-order hyperbolic polaritons (HO-HPhPs) form high-momentum ray-like propagation within the bulk, efficient excitation of these modes, especially in contrast to the long-wavelength lower-momentum surface polariton propagating modes, has remained a challenge. Critically, the large momentum mismatch between these modes and free-space light, alongside the spatial mismatch between the sub-diffractional scatterer and the distinct modal distribution of HO-HPhPs, lead to a suppressed launching efficiency of these higher-order modes, limiting their use in nanophotonic applications. Here, we report the experimental observation of a 10-fold enhancement in the excitation efficiency of HO-HPhPs through the use of subsurface scatterers over traditional surface scattering (e.g. a flake edge or gold launcher) within single-crystalline α-MoO3 slabs. We employ full-wave numerical simulations to investigate the role of the spatial overlap between HO-HPhP modal distributions and the scatterer placement upon excitation efficiency. Furthermore, we develop a generalized process using transfer matrix method to selectively design modal HO-HPhP excitation, which advances the capabilities of HPhP multiplexing for on-chip applications.
