Superscattering-enhanced narrow band forward scattering antenna

• 作者: 张志友 杜惊雷 胡德骄
• 来源期刊: 中国物理B（英文版）
• 关键词: surface plasmons optical antenna directional scattering Fano resonance
• 年，卷（期）: 2015,（10）
• 页码范围: 104202-1-104202-4
• 页数: 1页
• 语种: 英文
• DOI: 10.1088/1674-1056/24/10/104202

摘要

We present a narrow band forward scattering optical antenna which is based on the excitation of distinctive whispering gallery modes (WGMs). The antenna is composed of three coaxial cylinder layers:a dielectric layer is sandwiched between a metallic core and cladding. Owing to the destructive interference between the scattering of the outer metallic cladding and the WGM in the backward direction, the power fl ow in the forward direction is increased. Simulation and analysis show that in proper geometry conditions, the cavity can be tuned into a superscattering state. At this state, both the zeroth and the first order of WGM are excited and contribute to the total scattering. It is shown that the power ratio (power towards backward divided by power towards forward ) can be enhanced to about 27 times larger than that for a non-resonant position by the superscattering. Owing to the confinement of the cladding to WGMs, the wavelength range of effective forward scattering is considerably narrow (about 15 nm).