  Photonic devices exhibiting all-optically reconfigurable polarization
dependence with a large dynamic range would be highly attractive for active
polarization control. Here, we report that strongly polarization-selective
nonlinear optomechanical interactions emerge in subwavelength waveguides. By
using full-vectorial finite element analysis, we find that at certain core
ellipticities (aspect ratios) the forward simulated light scattering mediated
by a specific acoustic mode is eliminated for one polarization mode, whereas
that for the other polarization mode is rather enhanced. This intriguing
phenomenon can be explained by the interplay between the electrostrictive force
and radiation pressure and turns out to be tailorable by choice of waveguide
materials.
