Bar-Lev Doron, Scheuer Jacob
Opt Express. 2013 Dec 2;21(24):29165-78. doi: 10.1364/OE.21.029165.
We study theoretically various design considerations for efficient generation of second harmonic using a nonlinear substrate patterned with nano-antennas. The analysis is focused on a gap Bowtie nano-antenna array recessed in LiNbO₃ which is shown to be preferable over on surface structures due to field enhancement, field profile and linear and non-linear polarization considerations. In addition, we develop the nano-antenna counterpart of the Boyd-Klienmann model in order to analyze the impact of a Gaussian shaped fundamental beam on the generated second harmonic. Finally, we show that the dielectric properties of the substrate lead to preferable directions for the incident fundamental harmonic and the emission of the second harmonic. Our analyses lead to several design rules which can enhance second and high harmonic generation from nano-antennas arrays by several orders of magnitude.
我们从理论上研究了使用纳米天线图案化的非线性衬底高效产生二次谐波的各种设计考量。分析聚焦于嵌入铌酸锂中的间隙蝴蝶结纳米天线阵列，由于场增强、场分布以及线性和非线性极化方面的考虑，该阵列比表面结构更具优势。此外，我们开发了博伊德 - 克莱因曼模型的纳米天线对应模型，以分析高斯形状的基波光束对产生的二次谐波的影响。最后，我们表明衬底的介电特性导致了入射基波和谐波以及二次谐波发射的优选方向。我们的分析得出了几条设计规则，这些规则可以将纳米天线阵列产生的二次谐波和高次谐波提高几个数量级。
