Abstract We numerically studied the spin-dependent optical torque on a 2D chiral plasmonic nanomotor excited by circularly polarized lights. An interesting phenomenon of so-called negative optical torque is demonstrated on condition that the scattering optical torque is opposite to and larger than absorption optical torque under a plasmonic resonance of dipolar mode. Moreover, the calculated optical torque, exerted on the nanomotor, is monotonically tunable depending on the ellipticity of light. It is theoretically estimated that the spin-dependent rotation frequency can be modulated from about 3.56 kHz to 8.91 kHz under incident intensity of 1 mW ∕ μ m 2 . Our results demonstrate a counterintuitive rotation phenomenon on light-driven 2D chiral nanomotor, and open a manipulation avenue to control optically-induced torque via absorption and/or scattering of light by 2D chiral plasmonic meta-atom.

中文翻译：

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由于偶极散射，自旋相关二维手性纳米马达中的负光学扭矩

摘要 我们数值研究了由圆偏振光激发的二维手性等离子体纳米马达的自旋相关光学扭矩。在偶极模式等离子体共振下散射光力矩与吸收光力矩相反并大于吸收光力矩的条件下，证明了所谓的负光力矩的有趣现象。此外，计算出的施加在纳米马达上的光学扭矩可以根据光的椭圆度单调可调。理论上估计，在 1 mW ∕ μ m 2 的入射强度下，与自旋相关的旋转频率可以从大约 3.56 kHz 调制到 8.91 kHz。我们的结果证明了光驱动二维手性纳米马达的反直觉旋转现象，