PDF(Pubmed)
Abstract：
Non-conventional resonances, both acoustic and photonic, are found in metallic particles with a toroidal nanopropeller geometry, which is generated by sweeping a three-lobed 2D shape along a spiral with twisting angle α. For both optical and acoustic cases, the spectral location of resonances experiences a red-shift as a function of α. We demonstrate that the optical case can be understood as a natural evolution of resonances as the spiral length of the toroidal nanopropeller increases with α, implying a huge helicity-dependent absorption cross-section. In the case of acoustic response, two red-shifting breathing modes are identified. Additionally, even a small α allows the appearance of new low-frequency resonances, whose spectral dispersion depends on a competition between the length of the generative spiral and the pitch of the toroidal nanopropeller.
摘要：
非常规共振，声学和光子，在具有环形纳米螺旋桨几何形状的金属颗粒中发现，它是通过沿着具有扭转角α的螺旋扫描三瓣2D形状而生成的。对于光学和声学情况，共振的光谱位置经历作为α的函数的红移。我们证明，随着环形纳米螺旋桨的螺旋长度随α增加，光学情况可以理解为共振的自然演化，意味着一个巨大的依赖于螺旋度的吸收截面。在声学响应的情况下，确定了两种红移呼吸模式。此外,即使是很小的α也可以出现新的低频共振，其光谱色散取决于生成螺旋的长度和环形纳米螺旋桨的螺距之间的竞争。
