Theory study of domain visibility optimization in single rotating compensator Kerr microscopy

In this work, an optical elements azimuth optimization method in single rotating compensator domain imaging system was provided to improve the domain image visibility. After that, simulations were performed on 200 nm permalloy films and results displayed that the Kerr rotations exhibited a periodic increase-maximum-decrease tendency with the compensator rotating in one period. The Kerr effect enhancement can be achieved by collecting the light intensity at four compensator azimuths in a rotating period of the compensator. Furthermore, simulation results indicated that this method could effectively enhance the domain image contrast and signal-to-noise ratio of the permalloy film by setting the polarizer and analyzer at the optimal azimuth. What's more, to confirm the validity of this method, simulations were performed on 200 nm optically anisotropic cobalt film. The 2D image contrast figure indicated that unlike the isotropic permalloy film, there existed two large image contrast regions which are corresponding well to the extraordinary and ordinary light vector of the reflected light.