Fig. 1: Scheme for the lateral optical force arising from polarization-induced mirror symmetry breaking in an SO(2) rotationally symmetric system.
From: Dynamics of polarization-tuned mirror symmetry breaking in a rotationally symmetric system
a Schematic illustration of the lateral optical force acting on an object with SO(2) continuous rotational symmetry. A linearly polarized plane wave with a polarization angle α obliquely illuminates onto the object at an incident angle θ. The objects have only one axis of rotational symmetry, such as a cone, a cylinder, a dimer and a lens, etc., as shown in the inset. b At a diagonal polarization (such as α = 45°), the mirror symmetry with respect to the xz-plane of the light-matter interaction is broken and the lateral scattering optical momentum P-y in the -y direction is greater than the lateral scattering optical momentum P+y in the +y direction. Consequently, the lateral total momentum conservation results in a lateral optical force Fy along the +y direction. c, d For a s-or p-polarized plane wave (α = 0° or α = 90°), the light-matter interaction holds mirror symmetry, thus yielding a vanishing lateral optical force Fy. e–i The scattering near-field |Ez| in the yz-plane (x = 0) of the five SO(2) rotationally symmetric objects at the polarization angle α = 45°, incident angle θ = 60°. j The degree of mirror symmetry breaking (DMSB) of the five objects depends sinusoidally on the polarization angle α. k Numerically calculated lateral optical force Fy shows a sin(2α) dependence on the polarization angle α for the SO(2) rotationally symmetric objects.
