Panov Andrey V
Opt Lett. 2020 Jun 1;45(11):3071-3074. doi: 10.1364/OL.391991.
The nonlinear optical properties of the high-index nanoparticles are boosted at the anapole state. Researchers intensively study this phenomenon as being promising for various applications. In this Letter, the nonlinear optical Kerr effect of disordered and square lattice metasurfaces of GaP nanodisks is investigated as a function of the disk size in the vicinity of the anapole state at the wavelength of 532 nm. When the sizes of the nanodisks are close to the anapole state, the effective second-order refractive index of the metasurface increases exponentially. On approaching the anapole state, the sign of the effective second-order refractive index is inverted. The absolute value of the effective nonlinear Kerr coefficient of the square lattice metasurface is higher than that of the disordered array of nanodisks. The absolute value of the effective second-order refractive index in proximity to the anapole state is an order of magnitude higher than that at non-anapole resonances of the disordered metasurfaces consisting of the nanodisks or spheres.
高折射率纳米粒子的非线性光学特性在零极点状态下得到增强。研究人员对这一现象进行了深入研究，因为它在各种应用中具有广阔前景。在本信函中，研究了波长为532 nm时，处于零极点状态附近的GaP纳米盘无序和方形晶格超表面的非线性光学克尔效应与盘尺寸的函数关系。当纳米盘尺寸接近零极点状态时，超表面的有效二阶折射率呈指数增加。接近零极点状态时，有效二阶折射率的符号会反转。方形晶格超表面的有效非线性克尔系数绝对值高于纳米盘无序阵列。接近零极点状态时有效二阶折射率的绝对值比由纳米盘或纳米球组成的无序超表面在非零极点共振时高一个数量级。
