Transverse spin and momentum in two-wave interference

Abstract

We analyze the interference field formed by two electromagnetic plane waves (with the same frequency but different wave vectors), and find that such field reveals a rich and highly non-trivial structure of the local momentum and spin densities. Despite the seemingly-planar and extensively-studied character of the two-wave system, we find that it possesses a transverse (out-of-plane) helicity-independent spin density, and also a transverse polarization-dependent momentum density with unusual physical properties. The polarization-dependent transverse momentum represents the so-called Belinfante spin momentum, which does not exert the usual optical pressure and it is considered as `virtual' in field theory. We perform analytical estimations and exact numerical simulations of the interaction of the two-wave field with probe Mie particles. The results of these calculations clearly indicate the straightforward detectability of the unusual spin and momentum properties in the two-wave field and strongly motivate their future experimental verifications.

13 pages, 4 figures, Supplementary Information, to appear in Phys. Rev. X

References in corpus (5)

• Optical alignment and spinning of laser-trapped microscopic particles
• Chiral nanophotonic waveguide interface based on spin-orbit coupling of light
• Characterizing optical chirality
• Measuring the Transverse Spin Density of Light
• Superoscillation in speckle patterns

Cited by in corpus (5)

• Optical momentum and angular momentum in complex media: From the Abraham-Minkowski debate to unusual properties of surface plasmon-polaritons
• Spacetime algebra as a powerful tool for electromagnetism
• The ubiquitous photonic wheel
• Transverse angular momentum in topological photonic crystals
• Lateral Chirality-sorting Optical Spin Forces in Evanescent Fields