Geometric phase due to helicity inversion of photons inside an optical fiber composed periodically of left- and right- handed media

Resonance amplification of left-handed transmission at optical frequencies by stimulated emission of radiation in active metamaterials

We demonstrate that left-handed resonance transmission from metallic metamaterial, composed of periodically arranged double rings, can be extended to visible spectrum by introducing an active medium layer as the substrate. The severe ohmic loss inside metals at optical frequencies is compensated by stimulated emission of radiation in this active system. Due to the resonance amplification mechanism of recently proposed lasing spaser, the left-handed transmission band can be restored up to 610 nm wavelength, in dependence on the gain coefficient of the active layer. Additionally, threshold gains…

Complete bandgaps in one-dimensional left-handed periodic structures

Artificially fabricated structures with periodically modulated parameters such as photonic crystals offer novel ways of controlling the flow of light due to the existence of a range of forbidden frequencies associated with a photonic bandgap. It is believed that modulation of the refractive index in all three spatial dimensions is required to open a complete bandgap and prevent the propagation of electromagnetic waves in all directions. Here we reveal that, in a sharp contrast to what was known before and contrary to the accepted physical intuition, a one-dimensional periodic structure contain…

On enhanced sensing of chiral molecules in optical cavities

The differential response of chiral molecules to incident left- and right- handed circularly polarized light is used for sensing the handedness of molecules. Currently, significant effort is directed towards enhancing weak differential signals from the molecules, with the goal of extending the capabilities of chiral spectrometers to lower molecular concentrations or small analyte volumes. Previously, optical cavities for enhancing vibrational circular dichroism have been introduced. Their enhancements are mediated by helicity-preserving cavity modes which maintain the handedness of light due t…

通过扭曲三曲枝纳米结构耦合光学模式中的吸收实现可调谐圆二色性

Tunable circular dichroism through absorption in coupled optical modes of twisted triskelia nanostructures

本文提出由两个堆叠三曲枝手性等离子体纳米元件构成的系统，通过调节间距与相对扭转角控制耦合光学模式，实现最高60%且光谱位置可调的圆二色性。

引力子的自旋霍尔效应和 Berry 曲率

Spin Hall effect and Berry curvature of gravitons from quantum field theory

本文基于线性化引力的量子场论，推导了右旋和左旋引力子的 Wigner 函数，并展示了在弯曲时空中的引力子自旋霍尔效应，该效应源于引力子的 Berry 曲率，导致引力子能量霍尔电流的 helicity 依赖性分裂，其大小恰好是光子对应自旋霍尔电流的两倍。

衬底诱导的平面介质结构最大光学手性

Substrate-induced maximum optical chirality of planar dielectric structures

本研究针对平面介质结构增强光学手性需打破面外镜面对称的难题，发现低折射率衬底可在非手性超构结构中诱导最大光学手性，通过谐振态展开微扰分析揭示其机制，并经光子晶体膜光透射实验验证。