发表机构
Linköping University; Beijing Normal University; Great Bay University（林雪平大学; 北京师范大学; 大湾区大学）
机构由 AI 辅助整理，请以论文原文为准。AI 中文总结
本文提出通过旋转导电张量使几何非手性纳米结构产生可调光学手性，并实验验证了可逆调控，为超表面同时控制手性与波前提供新范式。
AI 中文摘要
共振纳米结构对于光的手性控制非常强大，但通常被认为需要非手性几何结构。在此，我们证明光学手性可以在几何非手性纳米结构中通过独立线性响应的错位而出现。通过将各向异性等离子体介质的电导率张量相对于几何对称的纳米结构旋转，我们产生了一种自旋选择性光学响应，其幅度和手性可以连续调谐，包括左右手行为之间的可逆切换。我们使用对齐的等离子体导电聚合物，并通过控制其聚合物主链相对于其他相同矩形纳米天线的方向，在实验上实现了这一概念。这导致了强平面手性，并且还可以通过改变聚合物的载流子密度进行可逆调制。此外，通过这一原理制成的矩形元原子的旋转角度不仅编码了局部几何相位，还同时编码了局部光学手性。这为相位梯度超表面提供了一种新的设计范式，能够通过单一旋转自由度同时控制光学手性和波前。
英文摘要
Resonant nanostructures are powerful for chiral control of light, but widely assumed to require achiral geometry. Here we demonstrate that optical chirality can emerge in geometrically achiral nanostructures, through the misalignment of independent linear responses. By rotating the conductivity tensor of an anisotropic plasmonic medium relative to a geometrically symmetric nanostructure, we generate a spin-selective optical response that can be continuously tuned both in magnitude and handedness, including reversible switching between left- and right-handed behaviour. We experimentally realize this concept using an aligned plasmonic conducting polymer and by controlling the orientation of its polymer backbone relative to otherwise identical rectangular nanoantennas. This leads to strong planar chirality that can also be reversibly modulated by varying the carrier density of the polymer. Moreover, the rotation angle of rectangular meta-atoms made through this principle encodes no longer only the local geometric phase but simultaneously the local optical chirality. This enables a new design paradigm for phase-gradient metasurfaces , enabling simultaneous control of optical chirality and wavefronts through a single rotational degree of freedom.
