Polarization-Dependent Second Harmonic Diffraction from Resonant GaAs Metasurfaces
Polarization-Dependent Second Harmonic Diffraction from Resonant GaAs Metasurfaces
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DOI：
10.1021/acsphotonics.7b01533
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发表时间：
2018-05-01
期刊：
影响因子：
7
通讯作者：
Staude, Isabelle
中科院分区：
文献类型：
--
作者：
Loechner, Franz J. F.;Fedotova, Anna N.;Staude, Isabelle
共振半导体超颖表面是一种新兴的多功能非线性光子学平台。在这项工作中，我们调查的二次谐波产生的超颖表面组成的二维正方形阵列的砷化镓纳米柱作为一个函数的基波的偏振。为此，我们进行非线性二次谐波显微镜，其中泵波长调谐到超颖表面的共振。此外，在傅立叶空间中成像所生成的非线性信号允许我们分析所生成的二次谐波的空间特性。我们的实验表明，二次谐波主要发射到周期性排列的第一衍射级，并且其强度随基波的偏振角而变化。虽然这可以从GaAs非线性张量的结构中预期，但发现这种变化本身的特性取决于泵浦波长。有趣的是，我们表明，超颖表面可以扭转相对于非结构化的GaAs晶片的二次谐波的偏振依赖性。这些一般性的意见证实了使用简化模型的元表面的数值模拟。我们的研究结果提供了有价值的输入基于参数过程的超表面为基础的经典和量子光源的发展。
Resonant semiconductor metasurfaces are an emerging versatile platform for nonlinear photonics. In this work, we investigate second-harmonic generation from metasurfaces consisting of two-dimensional square arrays of gallium arsenide nanocylinders as a function of the polarization of the fundamental wave. To this end, we perform nonlinear second harmonic microscopy, where the pump wavelength is tuned to the resonances of the metasurfaces. Furthermore, imaging the generated nonlinear signal in Fourier space allows us to analyze the spatial properties of the generated second harmonic. Our experiments reveal that the second harmonic is predominantly emitted into the first diffraction orders of the periodic arrangements, and that its intensity varies with the polarization angle of the fundamental wave. While this can be expected from the structure of the GaAs nonlinear tensor, the characteristics of this variation itself are found to depend on the pump wavelength. Interestingly, we show that the metasurface can reverse the polarization dependence of the second harmonic with respect to an unstructured GaAs wafer. These general observations are confirmed by numerical simulations using a simplified model for the metasurface. Our results provide valuable input for the development of metasurface-based classical and quantum light sources based on parametric processes.