Linearly polarised light induces torque on anisotropic plasmonic nanoparticles, which allows for the manipulation of their orientation. In this study, we calculate the torque induced on a plasmonic nanocuboid by modelling the surface plasmon resonance (SPR) as a driven damped harmonic oscillator. Using numerical simulations, we demonstrate the model’s accuracy in predicting the torque induced for narrow nanocuboids. We also investigate the effects of varying the nanocuboid’s width on the torque and demonstrate that the torque behaviour exhibits drastic changes, with the formation and modification of additional modes, particularly at the transverse SPR wavelength. As the torque arises from the movement of charges, we utilize charge distribution profiles to explain this shift in torque behaviour.

中文翻译：

---

等离子体纳米粒子建模：通过动态驱动阻尼谐振子模型和宽度相关效应揭示光学扭矩势

线性偏振光会在各向异性等离子体纳米颗粒上产生扭矩，从而可以操纵它们的方向。在这项研究中，我们通过将表面等离子体共振（SPR）建模为驱动阻尼谐振子来计算等离子体纳米长方体上感应的扭矩。通过数值模拟，我们证明了该模型在预测窄纳米长方体引起的扭矩方面的准确性。我们还研究了改变纳米长方体宽度对扭矩的影响，并证明随着附加模式的形成和修改，扭矩行为表现出巨大的变化，特别是在横向 SPR 波长处。由于扭矩是由电荷的运动产生的，我们利用电荷分布曲线来解释扭矩行为的这种变化。