Nauman Mudassar, de Ceglia Domenico, Yan Jingshi, Huang Lujun, Rahmani Mohsen, De Angelis Costantino, Miroshnichenko Andrey E, Lu Yuerui, Neshev Dragomir
School of Engineering, The Australian National University, Canberra, ACT 2601, Australia.
ARC Centre of Excellence for Transformative Meta-Optical Systems (TMOS), Department of Electronic Materials Engineering, Research School of Physics, The Australian National University, Canberra, ACT 2601, Australia.
Sci Adv. 2025 Aug 29;11(35):eady2108. doi: 10.1126/sciadv.ady2108.
Transition metal dichalcogenides are promising quantum materials because of unique exciton-photon interactions. These interactions can be enhanced by coupling with resonant photonic structures, especially in the nonlinear light emission processes like second-harmonic generation (SHG). However, excitonic absorption may dampen SHG. Here, we demonstrate tunable SHG enhancement using virtual coupling effects between quasi-bound state in the continuum (qBIC) optical resonances and tunable excitons in high-index WS metasurfaces with crescent meta-atoms. These metasurfaces promote a magnetic-type qBIC resonance, enabling control over nonlinear optical processes in the visible spectrum. The used qBIC resonance at half the exciton energy increases SHG efficiency by 98-fold compared to monolayer WS and by four orders of magnitude relative to an unpatterned WS film. The enhancement is tunable with temperature and incident light polarization, allowing the dynamic control of virtual coupling and SHG efficiency, thereby paving the way for next-generation reconfigurable metaoptics devices.
过渡金属二硫属化物因其独特的激子 - 光子相互作用而成为有前景的量子材料。通过与共振光子结构耦合，这些相互作用可以得到增强，特别是在诸如二次谐波产生（SHG）等非线性光发射过程中。然而，激子吸收可能会抑制SHG。在这里，我们展示了利用连续谱中的准束缚态（qBIC）光学共振与具有新月形元原子的高折射率WS超表面中可调谐激子之间的虚拟耦合效应来实现可调谐的SHG增强。这些超表面促进了一种磁型qBIC共振，能够控制可见光谱中的非线性光学过程。与单层WS相比，在激子能量一半处使用的qBIC共振使SHG效率提高了98倍，相对于未图案化的WS薄膜提高了四个数量级。这种增强可随温度和入射光偏振进行调节，从而实现对虚拟耦合和SHG效率的动态控制，为下一代可重构超光学器件铺平了道路。
