Plasmonic hotspot arrays boost second harmonic generation in thin-film lithium niobate

• DOI: 10.1364/oe.520773
• Publication Date: 2024-03-15T10:00:20Z
• Authors: Zengya Li; Xiaona Ye; Zhuoran Hu; Hao Li; Shijie Liu; Yuanlin Zheng; Xianfeng Chen
• Keywords: Nanophotonics

Focusing light down to subwavelength scales enhance the light-matter interaction has been highly sought after, which promoted significant researches and applications in nanophotonics. Plasmonic nanoantennae are a tool achieve this goal since they can confine into ultra-small volumes far below diffraction limit. However, metallic materials have property of central symmetry, resulting weak second-order nonlinear effects. Here, we design plasmonic bowtie on thin-film lithium niobate (TFLN) for deep-subwavelength confinement boost second-harmonic generation (SHG) TFLN via hotspot enhancement. The SHG enhancement factor about 20 times as compared unpatterned is achieved experiment when resonantly excited by femtosecond laser. This work proposes route optics platform.