Orbital-to-spin angular momentum conversion employing local helicity

Nechayev S, Eismann J, Leuchs G, Banzer P (2019)

Publication Type: Journal article

Publication year: 2019

Journal

Physical Review B American Physical Society

Book Volume: 99

Journal Issue: 7

DOI: 10.1103/PhysRevB.99.075155

Abstract

Spin-orbit interactions in optics traditionally describe an influence of the polarization degree of freedom of light on its spatial properties. The most prominent example is the generation of a spin-dependent optical vortex upon focusing or scattering of a circularly polarized plane wave by a nanoparticle, converting spin to orbital angular momentum of light. Here we present a mechanism of conversion of orbital-to-spin angular momentum of light upon scattering of a linearly polarized vortex beam by a spherical silicon nanoparticle. We show that focused linearly polarized Laguerre-Gaussian beams of first order (l = +1) exhibit an -dependent spatial distribution of helicity density in the focal volume. By using a dipolar scatterer the helicity density can be manipulated locally, while influencing globally the spin and orbital angular momentum of the beam. Specifically, the scattered light can be purely circularly polarized with the handedness depending on the orbital angular momentum of the incident beam. We corroborate our findings with theoretical calculations and an experimental demonstration. Our work sheds light on the global and local properties of helicity conservation laws in electromagnetism.

Authors with CRIS profile

Jörg Eismann Lehrstuhl für Experimentalphysik (Optik) Gerhard Leuchs Lehrstuhl für Experimentalphysik (Optik) Peter Banzer Lehrstuhl für Experimentalphysik (Optik)

Involved external institutions

Max-Planck-Institut für die Physik des Lichts (MPL) / Max Planck Institute for the Science of Light DE Germany (DE)

How to cite

APA:

Nechayev, S., Eismann, J., Leuchs, G., & Banzer, P. (2019). Orbital-to-spin angular momentum conversion employing local helicity. Physical Review B, 99(7). https://dx.doi.org/10.1103/PhysRevB.99.075155

MLA:

Nechayev, Sergey, et al. "Orbital-to-spin angular momentum conversion employing local helicity." Physical Review B 99.7 (2019).

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