We study light emission from square arrays of Mie-resonant silicon nanoantennas situated on a fluorescent glass substrate. When the spectral positions of the silicon nanoantennas’ resonances overlap with the intrinsic emission from the glass, the emission is selectively enhanced for certain spectral and spatial frequencies detemined by the design of the nanoantenna array. We measure the emission spectra of the coupled system for a systematic variation of the nanoantenna geometry, showing that the spectral maximum of the emission coincides with the antenna resonance positions observed in linear-optical transmittance spectra. Furthermore, we study the directionality of the emission by back focal plane imaging and numerical calculations based on the Fourier modal method and the reciprocity principle. We observe that the nanoantenna array induces a reshaping of the resonantly enhanced emission in the air half-space into a narrow lobe directed out of the substrate plane. This reshaping is explained by coherent scattering of the emitted light in the nanoantenna array. Our results demonstrate that combining emission enhancement by magnetic dipolar Mie-type resonances of silicon nanoantennas with diffractive coupling in the periodic arrangement allows for the creation of flat light sources with tailored spectral and directional emission properties.

中文翻译：

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三重谐振硅纳米天线阵列的光定向和光谱整形

我们研究了位于荧光玻璃基板上的米氏共振硅纳米天线的方形阵列的光发射。当硅纳米天线共振的频谱位置与玻璃的本征发射重叠时，对于通过纳米天线阵列设计确定的某些频谱和空间频率，有选择地增强了发射。我们测量了纳米天线几何形状的系统变化的耦合系统的发射光谱，表明发射的光谱最大值与线性光学透射光谱中观察到的天线谐振位置一致。此外，我们通过后焦平面成像和基于傅里叶模态方法和互易原理的数值计算研究了发射的方向性。我们观察到，纳米天线阵列在空气半空间中引起共振增强发射的重塑成指向基板平面之外的狭窄波瓣。这种重塑通过纳米天线阵列中发射光的相干散射来解释。我们的结果表明，通过周期性排列的衍射耦合将硅纳米天线的磁偶极Mie型共振增强的发射与衍射耦合相结合，可以创建具有定制的光谱和方向发射特性的平面光源。