Imbert–Fedorov shifts of a Gaussian beam reflected from anisotropic topological insulators

We study the Imbert–Fedorov (IF) shifts of a reflected Gaussian beam from anisotropic topological insulators (TIs). Aiming, respectively, at the two types of TI surface perturbations that can alter the surface optical properties, i.e., a magnetic coating and an applied magnetic field, we discuss the dependences of the IF shifts on the axion field, the TI's extent of anisotropy, the angle of incidence and the applied magnetic field. For a left-elliptically polarized incident beam, a positive (negative) axion field can lead to the decrease (increase) of the IF shifts relative to a conventional insulator in the magnetic coating case, and in the applied magnetic field case, the crossover of the IF shifts between the positive and the negative values can be realized by adjusting some external parameters. Also, the properties of the IF shifts are discussed for linearly and circularly-polarized incident beams. The results show that TI might be a desirable candidate for controlling flexibly the IF shifts.