Optical helicity of unpolarized light

Abstract

Recently arXiv:2004.02970 showed that the extraordinary transverse spin momentum density of spatially confined optical fields is largely independent of polarization. Here it is shown that 3D structured optical vortices which possess the phase factor $exp(il\varphi )$ have a contribution to the optical helicity density which is completely independent of polarization. In stark contrast to what is known in classical optics with plane waves and paraxial light, the physical consequence is that unpolarized light can exhibit optical activity and chiral light-matter interactions.

References in corpus (17)

• Spin-orbit interactions of light
• Chiral Quantum Optics
• Transverse and longitudinal angular momenta of light
• Extraordinary momentum and spin in evanescent waves
• Dual electromagnetism: Helicity, spin, momentum, and angular momentum
• Measuring the Transverse Spin Density of Light
• Conservation of the spin and orbital angular momenta in electromagnetism
• Transverse spinning of unpolarized light
• Transverse spin dynamics of light: the generalized spin-momentum locking for structured guided modes
• Geometric interpretation of the 3-dimensional coherence matrix for nonparaxial polarization
• Interaction of light carrying orbital angular momentum with a chiral dipolar scatterer
• The magnetic and electric transverse spin density of spatially confined light
• Optical vortex dichroism in chiral particles
• Relevance of Longitudinal Fields of Paraxial Optical Vortices
• Orbital-to-Spin Angular Momentum Conversion Employing Local Helicity
• The ubiquitous photonic wheel
• Kelvin's Chirality of Optical Beams

Cited by in corpus (13)

• The Application of Tailored Fields for Studying Chirality and Symmetry
• Enantioselective optical gradient forces using 3D structured vortex light
• Customized optical chirality of vortex structured light through state and degree of polarization control
• Nonlinear vortex dichroism in chiral molecules
• Topological-charge-dependent dichroism and birefringence of optical vortices
• Helicity, chirality and spin of optical fields without vector potentials
• On the orbit-induced spin density of tightly focused optical vortex beams: ellipticity and helicity
• Optical properties of radially-polarised twisted light
• The Azimuthally-Radially Polarized Beam: Helicity and Momentum Densities, Generation and Optimal Chiral Light
• Imaging the transverse spin density of light via electromagnetically induced transparency
• Generating optical angular momentum through wavefront curvature
• One more time on the helicity decomposition of spin and orbital optical currents
• Experimental generation of optimally chiral azimuthally-radially polarized beams