Spin photonic forces in non-reciprocal waveguides

Sarang Pendharker, Farid Kalhor, Todd Van Mechelen, Saman Jahani, Neda Nazemifard, Thomas Thundat, and Zubin Jacob. 8/30/2018.

Spin photonic forces in non-reciprocal waveguides

. Optics Express, 26, 18, Pp. 23898-23910.
Copy at https://is.gd/qljHc4
See also: Spin, Photonics


Optical forces acting on particles - controlled by the intensity, polarization and direction of optical beams - have become an important tool in manipulation, sorting and analysis of nano/micro-particles. The nature of these forces has been well understood in reciprocal structures exhibiting time-reversal symmetries. Here, we investigate the nature of optical forces in non-reciprocal structures with non-degenerate counter-propagating modes. We consider the specific case of non-reciprocity induced via translational motion and show that the two counter-propagating modes in a moving slab-waveguide are not degenerate which results in a non-zero lateral and longitudinal force on a nanoparticle. We prove that these anomalous forces are fundamentally connected to near-field photonic spin in optical waveguides and explain their directionality using universal spin-momentum locking of evanescent waves. The presented results show that the interplay of photon spin and non-reciprocity can lead to unique avenues of controlling nanoscale optical forces on-chip.

Last updated on 09/17/2021