Unidirectional scattering exploited transverse displacement sensor with tunable measuring range.
Wuyun Shang, Fajun Xiao, Weiren Zhu, Lei Han, Malin Premaratne, Ting Mei, Jianlin Zhao
Optics Express | Published : 2019
We propose a scheme to extend the measuring range of a transverse displacement sensor by exploiting the interaction of an azimuthally polarized beam (APB) with a single metal-dielectric core-shell nanoparticle. The focused APB illumination induces a longitudinal magnetic dipole (MD) in the core-shell nanoparticle, which interferes with the induced transverse electric dipole (ED) to bring forth a transverse unidirectional scattering at a specific position within the focal plane. Emphatically, the rapidly varying electromagnetic field within the focal plane of an APB leads to a remarkable sensitivity of the far-field scattering directivity to nanoscale displacements as the nanoparticle moves a..View full abstract