Opt Lett. 2018 Apr 15;43(8):1826-1829. doi: 10.1364/OL.43.001826.
Dissipative loss in optical materials is considered one of the major challenges in nano-optics. Here we show that, counter-intuitively, a large imaginary part of material permittivity contributes positively to subwavelength light enhancement and confinement. The Purcell factor and the fluorescence enhancement of dissipative dielectric bowtie nanoantennas, such as Si in ultraviolet (UV), are demonstrated to be orders of magnitude higher than their lossless dielectric counterparts, which is particularly favorable in deep UV applications where metals are plasmonically inactive. The loss-facilitated field enhancement is the result of a large material property contrast and an electric field discontinuity. These dissipative dielectric nanostructures can be easily achieved with a great variety of dielectrics at their Lorentz oscillation frequencies, thus having the potential to build a completely new material platform boosting light-matter interaction over broader frequency ranges, with advantages such as bio-compatibility, CMOS compatibility, and harsh environment endurance.
光学材料中的耗散损失被认为是纳米光学中的主要挑战之一。在这里，我们表明，与直觉相反，材料介电常数的大虚部对亚波长光增强和限制有积极贡献。我们证明，与无损耗介电材料相比，具有耗散特性的电介质蝶形纳米天线（例如在紫外光（UV）下的硅）的普塞尔因子和荧光增强要高出几个数量级，这在深紫外应用中非常有利，因为在深紫外应用中金属的等离子体是不活跃的。损耗促进的场增强是由于大的材料特性对比和电场不连续性。这些具有耗散特性的介电纳米结构可以在洛伦兹振荡频率处很容易地用各种介电材料来实现，因此有可能构建一个全新的材料平台，在更宽的频率范围内增强光物质相互作用，具有生物兼容性、CMOS 兼容性和恶劣环境耐受等优点。
