Sartorello Giovanni, Bocanegra Joshua, Knez David, Lukin Daniil M, Yang Joshua, Vučković Jelena, Fishman Dmitry A, Shvets Gennady, Shcherbakov Maxim R
School of Applied and Engineering Physics, Cornell University, Ithaca, NY 14850, USA.
Department of Electrical Engineering and Computer Science, University of California, Irvine, CA 92697, USA.
Nanophotonics. 2024 Jul 24;13(18):3395-3402. doi: 10.1515/nanoph-2024-0203. eCollection 2024 Aug.
Nanophotonic structures have shown promising routes to controlling and enhancing nonlinear optical processes at the nanoscale. However, most nonlinear nanostructures require a handling substrate, reducing their application scope. Due to the underwhelming heat dissipation, it has been a challenge to evaluate the nonlinear optical properties of free-standing nanostructures. Here, we overcome this challenge by performing shot-controlled fifth harmonic generation (FHG) measurements on a SiC meta-membrane - a free-standing transmission metasurface with pronounced optical resonances in the mid-infrared ( ≈ 4,000 nm). Back focal plane imaging of the FHG diffraction orders and rigorous finite-difference time-domain simulations reveal at least two orders of magnitude enhancement of the FHG from the meta-membrane, compared to the unstructured SiC film of the same thickness. Single-shot measurements of the meta-membrane with varying resonance positions reveal an unusual spectral behavior that we explain with Kerr-driven intensity-dependent resonance dynamics. This work paves the way for novel substrate-less nanophotonic architectures.
纳米光子结构已展现出在纳米尺度上控制和增强非线性光学过程的可行途径。然而，大多数非线性纳米结构需要一个支撑衬底，这限制了它们的应用范围。由于散热不佳，评估独立纳米结构的非线性光学性质一直是个挑战。在此，我们通过对碳化硅超膜进行单脉冲控制的五次谐波产生（FHG）测量来克服这一挑战，该碳化硅超膜是一种独立的透射超表面，在中红外波段（≈4000纳米）具有明显的光学共振。对FHG衍射级的背焦平面成像以及严格的时域有限差分模拟表明，与相同厚度的非结构化碳化硅薄膜相比，超膜的FHG增强了至少两个数量级。对具有不同共振位置的超膜进行的单脉冲测量揭示了一种不寻常的光谱行为，我们用克尔驱动的强度依赖共振动力学对此进行了解释。这项工作为新型无衬底纳米光子架构铺平了道路。
