Two-dimensional (2D) transition metal dichalcogenides (TMDs) attain increasing attention due to their exceptional nonlinear optical efficiencies, which hold promising potential for on-chip photonics and advanced optoelectronic applications. Planar TMDs have been proven to support orders-higher third-order nonlinear coefficients in comparison with common nonlinear materials. Interestingly, stronger light–matter interaction could be motivated when curved features are introduced to 2D TMDs. Here, a type of inorganic fullerene-like WS2 nanoparticles is chemically synthesized using hard mesoporous silica. By using the spatial self-phase modulation (SSPM) method, the nonlinear refractive index n2 and third-order susceptibility χ(3) are investigated in the visible range. It is found that n2∼10−5 cm2/W and χ(3)∼10−7 esu, two orders higher than the counterparts of planar WS2 structures. Our experimental findings provide a fresh thinking in designing nonlinear optical materials and endow TMDs with new potentials in photonic integration applications.

中文翻译：

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无机富勒烯类 WS2 纳米颗粒的优异三阶非线性

二维 (2D) 过渡金属二硫属化物 (TMD) 由于其卓越的非线性光学效率而受到越来越多的关注，其在片上光子学和先进的光电应用方面具有广阔的潜力。与普通非线性材料相比，平面 TMD 已被证明支持更高阶的三阶非线性系数。有趣的是，当将弯曲特征引入二维 TMD 时，可以激发更强的光-物质相互作用。在这里，使用硬介孔二氧化硅化学合成了一种无机富勒烯类 WS2 纳米粒子。通过使用空间自相位调制（SSPM）方法，在可见光范围内研究了非线性折射率n2和三阶磁化率χ(3)。发现 n2∼10−5 cm2/W 和 χ(3)∼10−7 esu，比平面 WS2 结构的对应物高两个数量级。我们的实验结果为设计非线性光学材料提供了一种全新的思路，并赋予 TMD 在光子集成应用中的新潜力。