ABSTRACT

Plasmonic resonators have drawn more attention due to the ability to confine light into subwavelength scale. However, they always suffer from a low-quality (Q) factor owing to the intrinsic loss of metal. Here, we numerically propose a plasmonic resonator with ultra-high Q factor based on plasmonic metal–insulator-metal (MIM) waveguide structures. The resonator consists of a disk cavity surrounded by a concentric ring cavity, possessing an ultra-small volume. Arising from the plasmon hybridization between plasmon modes in the disk and ring cavity, the induced bonding hybridized modes have an ultra-narrow full width at half maximum (FWHM) as well as ultra-high Q factors. The FWHM can be nearly 1 nm and Q factor can be more than 400. Furthermore, such a device can act as a refractive index sensor with an ultra-high figure of merit (FOM). This work provides a novel approach to design plasmonic high-Q-factor resonators and has potential on-chip applications such as filters, multi-spectral sensors and nanolasers.

摘要

由于能够将光限制在亚波长范围内，等离子谐振器引起了更多的关注。然而，由于金属的固有损失，它们总是受到低质量 (Q) 因素的影响。在这里，我们在数值上提出了一种基于等离子体金属-绝缘体-金属 (MIM) 波导结构的具有超高 Q 因子的等离子体谐振器。谐振器由一个被同心环腔包围的圆盘腔组成，具有超小的体积。由于圆盘和环形腔中等离子体模式之间的等离子体杂交，诱导键合杂交模式具有超窄的半峰全宽（FWHM）以及超高的 Q 因子。FWHM 可以接近 1 nm，Q 因子可以超过 400。此外，这种器件可以用作具有超高品质因数 (FOM) 的折射率传感器。