Anisotropic Goos–Hänchen shift in few-layer two-dimensional materials

We study the Goos–Hänchen (GH) effect in mechanically exfoliated anisotropic two-dimensional (2D) black phosphorus and rhenium disulfide by using a beam displacement amplification technique. We observed anisotropic GH shifts along different crystal orientations of two 2D materials, and they exhibit different anisotropy characteristics. It is because the GH shift is mainly affected by the phase shift of light in the 2D materials, which is related to the real part of the refractive index, while the absorption effect related to the imaginary part of the refractive index has negligible influence on the GH shift. The GH shift can be applied to explore the anisotropy of the real part of the refractive index of a 2D material. Our results provide an important way to reveal the anisotropy mechanism of 2D materials.