Controlling the directivity of emission and absorption at the nanoscale holds great promise for improving the performance of optoelectronic devices. Previously, directive structures have largely been centered in two categories-nanoscale antennas, and classical lenses. Herein, we utilize an evolutionary algorithm to design 3D dielectric nanophotonic lens structures leveraging both the interference-based control of antennas and the broadband operation of lenses. By sculpting the dielectric environment around an emitter, these nanolenses achieve directivities of 101 for point-sources, and 67 for finite-source nanowire emitters; 3× greater than that of a traditional spherical lens with nearly constant performance over a 200 nm wavelength range. The nanolenses are experimentally fabricated on GaAs nanowires, and characterized via photoluminescence Fourier microscopy, with an observed beaming half-angle of 3.5° and a measured directivity of 22. Simulations attribute the main limitation in the obtained directivity to imperfect alignment of the nanolens to the nanowire beneath.

中文翻译：

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宽带高定向3D纳米光子透镜。

在纳米尺度上控制发射和吸收的方向性对于改善光电器件的性能具有广阔的前景。以前，定向结构主要集中在两类上：纳米级天线和经典透镜。在本文中，我们利用一种进化算法来设计3D介电纳米光子透镜结构，从而充分利用天线的基于干扰的控制和透镜的宽带操作。通过雕刻发射器周围的介电环境，这些纳米透镜对点源的指向性达到101，对于有限源纳米线发射器的指向性达到67。比传统球面透镜大3倍，在200 nm波长范围内具有几乎恒定的性能。纳米透镜是在GaAs纳米线上实验制造的，