Enhancing optical nonlinearity Intense pulses of light interacting with a dielectric material can induce optical nonlinear behavior, whereby the frequency of the output light can be doubled or tripled or excited to even higher harmonics of the input light. Usually this interaction is weak and occurs over many thousands of wavelengths, typically requiring the combination of bulk volumes of material with a confining cavity. Using a mechanism of light confinement called bound states in the continuum, Koshelev et al. show that enhanced second-harmonic generation can be obtained in nanoscale subwavelength cylinders of a dielectric material. The results on these optical nanoantennas offer a platform for developing integrated nonlinear nanophotonic devices. Science, this issue p. 288 Nanoscale optical antennas can be designed to enhance optical nonlinearity. Subwavelength optical resonators made of high-index dielectric materials provide efficient ways to manipulate light at the nanoscale through mode interferences and enhancement of both electric and magnetic fields. Such Mie-resonant dielectric structures have low absorption, and their functionalities are limited predominantly by radiative losses. We implement a new physical mechanism for suppressing radiative losses of individual nanoscale resonators to engineer special modes with high quality factors: optical bound states in the continuum (BICs). We demonstrate that an individual subwavelength dielectric resonator hosting a BIC mode can boost nonlinear effects increasing second-harmonic generation efficiency. Our work suggests a route to use subwavelength high-index dielectric resonators for a strong enhancement of light–matter interactions with applications to nonlinear optics, nanoscale lasers, quantum photonics, and sensors.

中文翻译：

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用于非线性纳米光子学的亚波长介电谐振器

增强光学非线性 与介电材料相互作用的强光脉冲会引起光学非线性行为，从而使输出光的频率可以增加一倍或三倍，或激发到输入光的更高谐波。通常这种相互作用很弱，发生在数千个波长上，通常需要将大量材料与限制腔相结合。Koshelev 等人在连续介质中使用一种称为束缚态的光限制机制。表明可以在介电材料的纳米级亚波长圆柱体中获得增强的二次谐波产生。这些光学纳米天线的结果为开发集成非线性纳米光子器件提供了一个平台。科学，这个问题 p。可以设计 288 纳米级光学天线来增强光学非线性。由高指数介电材料制成的亚波长光学谐振器提供了通过模式干涉和电场和磁场增强在纳米尺度上操纵光的有效方法。这种米氏共振介电结构具有低吸收性，并且其功能主要受辐射损耗的限制。我们实施了一种新的物理机制来抑制单个纳米级谐振器的辐射损耗，以设计具有高质量因子的特殊模式：连续介质中的光学束缚态 (BIC)。我们证明了承载 BIC 模式的单个亚波长介电谐振器可以增强非线性效应，从而提高二次谐波产生效率。