High‐index dielectric nanoantennas excited at Mie‐type resonances have exhibited enormous enhancement of optical nonlinearity. Such nanostructures have been actively studied by researchers in recent years. Here, a numerical analysis study of the optical Kerr effect of nanocomposites consisting of high refractive index (GaP) spheres at the wavelength of 532 nm is presented. This is done by means of 3D finite‐difference time‐domain simulations. The effective nonlinear refractive index of 0.8 µm thick nanocomposites and metasurfaces is evaluated. It is shown that the optical Kerr nonlinearity of the nanocomposites rises by orders in proximity to Mie resonances and may exceed the second‐order refractive index of the bulk material. It is revealed that the sign of the effective optical Kerr coefficient is inverted near the Mie resonances. This effect may be of interest in developing nonlinear optical metadevices.

中文翻译：

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Mie共振附近随机高指数纳米复合材料光学Kerr非线性的巨增强和符号反转。

在米氏共振下激发的高折射率电介质纳米天线表现出极大的光学非线性增强。近年来，研究人员积极研究了这种纳米结构。在此，对由532 nm波长的高折射率（GaP）球组成的纳米复合材料的光学Kerr效应进行了数值分析研究。这是通过3D有限差分时域仿真来完成的。评估了0.8 µm厚的纳米复合材料和超表面的有效非线性折射率。结果表明，纳米复合材料的光学Kerr非线性随着接近Mie共振的增加而增加，并且可能超过块状材料的二阶折射率。发现有效光学克尔系数的符号在米氏共振附近反转。