2013/08/31 by Konstantin Y. Bliokh, A. Ya. Bekshaev, Aleksandr Y. Bekshaev +1 · 2 citations
Physics and Astronomy · #Mechanical and Optical Resonators #Orbital Angular Momentum in Optics #Quantum and Classical Electrodynamics #hep-th #physics.optics #quant-ph
paper · pdf · doi:10.1038/ncomms4300
published as Nature Communications 5:3300 (2014) · 14 pages, 3 figures + Supplementary Information: 21 pages, 5 figures, 1 table
openalex publication_date 2014/03/06 · arxiv created 2014/03/22 · arxiv updated 2014/03/25 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/01
Momentum and spin represent fundamental dynamical properties of quantum particles and fields. In particular, propagating optical waves (photons) carry momentum and longitudinal spin determined by the wave vector and circular polarization, respectively. Here we show that exactly the opposite can be the case for evanescent optical waves. A single evanescent wave possesses a spin component, which is independent of the polarization and is orthogonal to the wave vector. Furthermore, such a wave carries a momentum component, which is determined by the circular polarization and is also orthogonal to the wave vector. We show that these extraordinary properties reveal a fundamental Belinfante's spin momentum, known in field theory and unobservable in propagating fields. We demonstrate that the transverse momentum and spin push and twist a probe Mie particle in an evanescent field. This allows the observation of `impossible' properties of light and of a fundamental field-theory quantity, which was previously considered as `virtual'.