论文标题
聚焦光完全耦合到表面极化子
Complete Coupling of Focused Light to Surface Polaritons
论文作者
论文摘要
与传播光相比，表面极性子显示短的波长，从而实现了较大的空间浓度和电磁能的增强。然而，这种波长不匹配通常伴随着较差的光到极线耦合，这些耦合限制了光学传感和光电等区域中的潜在应用。在这里，我们通过证明将距平面表面距离合适的距离放置在合适距离处的小散射器可以使聚焦光束与表面极化子完全耦合。我们提出了与银膜和石墨烯中的光质耦合以及六角形硝化硼膜中的校正光耦合的严格理论结果。我们进一步为实现最大耦合所需的梁曲线和颗粒响应制定了详细的一般处方，我们通过对偶性散射器和有限尺寸颗粒进行分析计算来补充。我们的结果开辟了一条实用的途径，以绕过纳米光子学中长期的光子 - 两极波长不匹配问题。
Surface polaritons display short wavelengths compared to propagating light, thus enabling large spatial concentration and enhancement of electromagnetic energy. However, this wavelength mismatch is generally accompanied by poor light-to-polaritons coupling that limits potential applications in areas such as optical sensing and optoelectronics. Here, we address this problem by demonstrating that a small scatterer placed at a suitable distance from a planar surface can produce complete coupling of a focused light beam to surface polaritons. We present rigorous theoretical results for light coupling to plasmons in silver films and graphene, as well as phonon polaritons in hexagonal boron nitride films. We further formulate detailed general prescriptions on the beam profile and particle response that are required to achieve maximum coupling, which we supplement by analytical calculations for dipolar scatterers and finite-size particles. Our results open a practical route to circumvent the long-standing photon-polariton wavelength mismatch problem in nanophotonics.
