English (United Kingdom)

https://curated-unify.zendy.io/wp-json/zendy-region/v1/featured_content/oa?rat=en

https://curated-unify.zendy.io/wp-json/zendy-region/v1/highlighted_journal/

Global: Zendy Plus annual

Presents the access of premium content as premium feature

Premium Content

Presents the keyphrase highlighting as premium feature

Keyphrase Highlighting

Presents the summarisation as premium feature

Summarisation

Insights

Presents the pdf analysis as premium feature

PDF Analysis

Presents the zaia usage as premium feature

ZAIA

Global: Zendy Plus monthly

Global: Zendy Tools annual

Global: Zendy Tools monthly

Global: Zendy Free Plan

We demonstrate that tight focusing of a circularly polarized Gaussian beam inoptical tweezers leads to spin-momentum locking - with the transverse spinangular momentum density being independent of helicity, while the transversemomentum (Poynting vector) becomes helicity dependent. Our theoreticalcalculations, numerical simulations, and experiments reveal that the presenceof a stratified medium in the path of the trapping beam significantly enhancesthe magnitude of transverse momentum in the radial direction with respect tothe beam axis, and likewise, also leads to high off-axial intensity. Thisoverlap allows us to experimentally observe the circular motion of abirefringent particle, trapped off-axis, in response to an input circularlypolarized fundamental Gaussian beam carrying no intrinsic orbital angularmomentum. The circular motion is dependent on the helicity of the input beam,so that we can identify it to be the signature of the elusive Belinfante spinin propagating light beams obtained in our optical tweezers setup. Our work canbe extended to higher-order beams carrying intrinsic orbital angular momentumleading to simple routes of achieving complex particle manipulation usingoptical tweezers.

Direct observation of the effects of spin dependent momentum of light in optical tweezers