Ultrafast Optics and Nanophotonics Research Laboratory, University of Alberta, Edmonton, Alberta T6G 2V4, Canada.
Phys Rev Lett. 2015 Jun 5;114(22):227401. doi: 10.1103/PhysRevLett.114.227401. Epub 2015 Jun 4.
We report visible third-harmonic conversion at λ=517 nm in subwavelength silicon-based nanoplasmonic waveguides at an unprecedented conversion efficiency of 2.3×10^{-5}. This marks both the highest third-harmonic conversion efficiency in a silicon-based or nanoplasmonic structure and the smallest silicon waveguide structure demonstrated to date. The high conversion efficiency is attributed to tight electric field confinement and strong light-matter coupling arising from surface plasmon modes in the nanoplasmonic waveguide, enabling efficient nonlinear optical mixing over micrometer length scales. The nonresonant geometry of the waveguide enables the entire λ=1550 nm femtosecond pulse spectrum to be converted to its third harmonic, which may be easily extended to the entire visible spectrum. We envisage that third-harmonic generation in silicon-based nanoplasmonic waveguides could provide a platform for integrated, broadband visible light sources and entangled triplet photons on future hybrid electronic-silicon photonic chips.
我们在亚波长硅基纳米等离子体波导中报告了在 λ=517nm 处的可见三次谐波转换，转换效率达到了前所未有的 2.3×10^{-5}。这标志着硅基或纳米等离子体结构中最高的三次谐波转换效率，也是迄今为止展示的最小的硅波导结构。高转换效率归因于纳米等离子体波导中表面等离激元模式产生的紧密电场限制和强光物质耦合，从而实现了在微米长度尺度上的高效非线性光学混合。波导的非共振几何形状使得整个 λ=1550nm 的飞秒脉冲光谱能够转换为其三倍频，这很容易扩展到整个可见光谱。我们设想，硅基纳米等离子体波导中的三次谐波产生可能为未来混合电子-硅光子芯片上的集成、宽带可见光源和纠缠三重态光子提供平台。
