Boosting third-harmonic generation by a mirror-enhanced anapole resonator

• 来源期刊: 光：科学与应用（英文版）
• 年，卷（期）: 2018,（5）
• 页码范围: 430-437
• 页数: 8页
• 语种: 英文
• DOI: 10.1038/s41377-018-0051-8

摘要

We demonstrate that a dielectric anapole resonator on a metallic mirror can enhance the third harmonic emission by two orders of magnitude compared to a typical anapole resonator on an insulator substrate.By employing a gold mirror under a silicon nanodisk,we introduce a novel characteristic of the anapole mode through the spatial overlap of resonantly excited Cartesian electric and toroidal dipole modes.This is a remarkable improvement on the early demonstrations of the anapole mode in which the electric and toroidal modes interfere off-resonantly.Therefore,our system produces a significant near-field enhancement,facilitating the nonlinear process.Moreover,the mirror surface boosts the nonlinear emission via the free-charge oscillations within the interface,equivalent to producing a mirror image of the nonlinear source and the pump beneath the interface.We found that these improvements result in an extremely high experimentally obtained efficiency of 0.01％.