Robust enhancement of high-harmonic generation from all-dielectric metasurfaces enabled by polarization-insensitive bound states in the continuum.
Robust enhancement of high-harmonic generation from all-dielectric metasurfaces enabled by polarization-insensitive bound states in the continuum.
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通过连续体中的偏振不敏感束缚态，可以稳健增强全介电超表面的高次谐波生成。
作者：
Shuyuan Xiao;M. Qin;J. Duan;Tingting Liu
新兴的全电介质平台表现出高质量（Q）共振，其由驱动高效非线性光学过程的连续体（BIC）中的束缚态物理所支配。在这里，我们展示了由四个硅纳米盘组成的全介电超表面对三次谐波（THG）和五次谐波产生（FHG）的鲁棒增强。通过对称性破缺，真正的BIC转变为具有严格场约束的高Q准BIC共振，在中等泵浦强度（1GW/cm 2）下，获得了3.9 × 10-4 W-2和4.8 × 10-10 W-4的高三倍频效率和四倍频效率。此外，准BIC和共振增强谐波表现出偏振不敏感的特性，由于特殊的C4元原子的排列。我们的研究结果为智能设计高效、鲁棒的非线性纳米光子器件提供了思路。
The emerging all-dielectric platform exhibits high-quality (Q) resonances governed by the physics of bound states in the continuum (BIC) that drives highly efficient nonlinear optical processes. Here we demonstrate the robust enhancement of third-(THG) and fifth-harmonic generation (FHG) from all-dielectric metasurfaces composed of four silicon nanodisks. Through the symmetry breaking, the genuine BIC transforms into the high-Q quasi-BIC resonance with tight field confinement for record high THG efficiency of 3.9 × 10-4 W-2 and FHG efficiency of 4.8 × 10-10 W-4 using a moderate pump intensity of 1 GW/cm2. Moreover, the quasi-BIC and the resonantly enhanced harmonics exhibit polarization-insensitive characteristics due to the special C4 arrangement of meta-atoms. Our results suggest the way for smart design of efficient and robust nonlinear nanophotonic devices.