Hong Peilong, Xu Lei, Ying Cuifeng, Rahmani Mohsen
Opt Lett. 2022 May 1;47(9):2326-2329. doi: 10.1364/OL.453625.
We theoretically investigate boosting second-harmonic generation (SHG) of monolayer van der Waals crystals by employing flatband modes hosted by photonic moiré superlattices. Such a system with high quality factor and a monolayer crystal accommodated on the top of it, provides a unique opportunity to enhance and manipulate SHG emission. We show that employing a doubly resonant diagram on such a moiré superlattice system not only boosts the SHG, but also tunes the directional emission of the second-harmonic wave. Moreover, we demonstrate that a structured beam illumination could further boost SHG, with the phase structure retrieved through a two-beam second-harmonic interference configuration. These results suggest the flatband modes in moiré superlattice as a promising platform for boosting SHG with monolayer van der Waals crystals, offering new possibilities for developing compact nonlinear photonic devices.
我们从理论上研究了利用光子莫尔超晶格中的平带模式来增强单层范德华晶体的二次谐波产生（SHG）。这样一个具有高品质因数且顶部容纳单层晶体的系统，为增强和操纵SHG发射提供了独特的机会。我们表明，在这种莫尔超晶格系统上采用双共振图不仅能增强SHG，还能调节二次谐波波的定向发射。此外，我们证明结构化光束照明可以进一步增强SHG，通过双光束二次谐波干涉配置来恢复相位结构。这些结果表明，莫尔超晶格中的平带模式是利用单层范德华晶体增强SHG的一个有前途的平台，为开发紧凑型非线性光子器件提供了新的可能性。
