Zhang Boyi, Sato Rodrigo, Tanaka Miyoko, Takeda Yoshihiko
School of Pure and Applied Sciences, University of Tsukuba, Tsukuba, Ibaraki, 305-8577, Japan.
Center for Green Research on Energy and Environmental Materials, National Institute of Materials Science (NIMS), Tsukuba, Ibaraki, 305-0003, Japan.
Sci Rep. 2020 Aug 17;10(1):13855. doi: 10.1038/s41598-020-70868-4.
We experimentally investigated the spectral dependence of the third-order susceptibility [Formula: see text] of Au triangular nanoplates in a broad wavelength region (400-1,000 nm). Complex shaped plasmonic nanoparticles provide a promising route to achieve control of their optical properties at the nanoscale. However, little is known about the effects of geometrical parameters to the optical nonlinearities and underlying mechanisms of the plasmon modes. Here, we obtained the [Formula: see text] of Au triangular nanoplates featuring a narrow plasmon resonance that is tunable in the visible and near-IR regions. This work demonstrates that the plasmonic triangular nanoplates simultaneously shows self-focusing and -defocusing, and saturable and reverse-saturable absorption properties at specific wavelength regions. Maximum amplitudes of real and imaginary components are - 6.8 × 10 m/V at 668 nm and - 6.7 × 10 m/V at 646 nm, respectively. Spectral dependence of the quantity [Formula: see text] enables comparison between different shaped plasmonic NPs to boost active plasmonic applications performance.
我们通过实验研究了金三角形纳米板在宽波长区域（400 - 1000纳米）内三阶非线性极化率χ(3)的光谱依赖性。复杂形状的等离子体纳米颗粒为在纳米尺度上实现对其光学性质的控制提供了一条有前景的途径。然而，关于几何参数对光学非线性和等离子体模式潜在机制的影响却知之甚少。在此，我们获得了具有窄等离子体共振的金三角形纳米板的χ(3)，该共振在可见光和近红外区域是可调谐的。这项工作表明，等离子体三角形纳米板在特定波长区域同时表现出自聚焦和散焦，以及饱和和反饱和吸收特性。实部和虚部的最大振幅分别在668纳米处为 - 6.8×10⁻⁶ m/V 和在646纳米处为 - 6.7×10⁻⁶ m/V。χ(3)的光谱依赖性使得不同形状的等离子体纳米颗粒之间能够进行比较，以提高有源等离子体应用的性能。
