相关论文: On the conservation of helicity in a chiral medium
We present a new approach to the definition of optical helicity in a medium. Our approach resolves the problem that duality transformations which simultaneously combine $\mathbf{E}$ with $\mathbf{H}$ and $\mathbf{D}$ with $\mathbf{B}$ are…
Several dynamical properties such as energy, momentum, angular momentum, and optical helicity have been recently reexamined in dispersive and lossless media. Here, we address a parallel derivation for the optical chirality, extending it so…
Polarization-dependent dynamical properties of light as the spin angular momentum (SAM), helicity, and chirality are conserved quantities in free-space. Despite their similarities on account of their relationship with a circular state of…
Two conditions on symmetries are identified as necessary for a linear scattering system to be able to rotate the linear polarisation of light: Lack of at least one mirror plane of symmetry and electromagnetic duality symmetry. Duality…
We discuss optical chirality in different types of gyrotropic media. Our analysis is based on the formalism of nongeometric symmetries of Maxwell's equations in vacuum generalized to material media with given constituent relations. This…
Structured light enables the characterization of chirality of optically small nanoparticles by taking advantage of the helicity maximization concept recently introduced in[1]. By referring to fields with nonzero helicity density as chiral…
The helicity of a free massless relativistic particle, $\chi^o={\bf s}.{\bf p}/|{\bf p}|$, is generalized, for a particle in an electromagnetic field, to $\chi={\bf s}.{\bf p}/{\cal E}$, where ${\cal E}$ is the modified kinetic energy. Both…
This paper develops, in precise quantum electrodynamic terms, photonic attributes of the "optical chirality density", one of several measures long known to be conserved quantities for a vacuum electromagnetic field. The analysis lends…
Helicity preserving nanostructures and metasurfaces have been recently proposed as suitable candidates to enhance spectroscopic features of chiral matter. With this in mind, we highlight that losses in the constituent nonmagnetic materials…
Optical helicity density is usually discussed for monochromatic electromagnetic fields in free space. It plays an important role in the interaction with chiral molecules or nanoparticles. Here we introduce the optical helicity density in a…
Helicity is a universal quantity describing the internal rotation of an object or a field. Whether it characterizes fundamental properties such as the spin of elementary particles or leads to practical consequences such as the toxicity or…
We propose the concept of helicity maximization applicable to structured light and obtain a universal rela-tion for the maximum of helicity density at a given field energy density. We further demonstrate that us-ing structured light with…
We theoretically study circular dichroism of chiral molecules embedded inside a helicity-preserving Fabry-P\'erot cavity. We find an increase of the intrinsic chiroptical response of the molecules by 2 orders of magnitude and report the…
We introduce a definition of the electromagnetic chirality of an object and show that it has an upper bound. Reciprocal objects attain the upper bound if and only if they are transparent for all the fields of one polarization handedness…
Based on a recent unified formulation on dichorism and extinction of helicity on scattering by a small particle, dipolar in the wide sense, magnetodielectric or not, chiral or achiral, we show that such extinction is enhanced not only at…
We present simple derivations of nuclear $\beta$-decay correlations with an emphasis on the special role of helicity. This provides a good opportunity to teach students about helicity and chirality in particle physics through exercises…
We examine the recently introduced measure of chirality of a monochromatic optical field [Y. Tang and A. E. Cohen, Phys. Rev. Lett. 104, 163901 (2010)] using the momentum (plane-wave) representation and helicity basis. Our analysis…
We put forward the physical meaning of the conservation equation for the helicity on scattering of an electromagnetic field with a generally magnetodielectric bi-isotropic dipolar object. This is the optical theorem for the helicity that,…
The chirality and helicity of linearly polarised Laguerre-Gaussian (LG) beams are examined. Such a type of light possesses a substantial longitudinal field when its beam waist is sufficiently small and so gives rise to non-zero chirality…
Magnetic field is unstable in a medium with time-independent chiral conductivity. Owing to the chiral anomaly, the electromagnetic field and the medium exchange helicity which results in time-evolution of the chiral conductivity. Using the…