Spin-Dependent Splitting Rotation of a Gaussian Beam Reflected From an Air–Glass Interface

Abstract

We investigate the spin-dependent splitting systematically by considering spin Hall effect of light and in-plane spin separation of light simultaneously, when a Gaussian beam is reflected from an air-glass interface. It is revealed that there exhibits a spin-dependent splitting rotation with the increase of the polarization angle, and the rotation direction and speed can be controlled by the incident angle. Remarkably, with the polarization angle increasing from 0 $^\circ$ to 90 $^\circ$ , the splitting rotates 180 $^\circ$ clockwise in total when the incident angle is less than Brewster angle, whereas it rotates an angle under 90 $^\circ$ counterclockwise first and then clockwise return to the original position when the incident angle is larger than Brewster angle. Their initial rotation speeds of splitting to $x_r$ direction both become larger as the incident angle approaches to Brewster angle, therefore when the incident angle is equal to Brewster angle, the splitting only forms a 90 $^\circ$ clockwise rotation. These general laws of spin-dependent splitting rotation are demonstrated by instances, and the rotation behaviors are considered as a result of various proportions of transverse spin separation and in-plane spin separation. This research provides a feasible way to manipulate the photon spin in optical nanodevice.