▎ 摘　　要

The Goos-Hlinchen (GH) shift and Imbert-Fedorov (IF) shift caused by light-matter and spin-orbit interactions can reveal the intrinsic properties of nanomaterials. We propose a beam displacement amplification technique (BDAT) that can break the optical diffraction limit in beam displacement measurements. The displacement resolution of the BDAT is 4 nm, and the detection size is 5 mu m, which is very suitable for the displacement measurement of mechanically exfoliated two-dimensional (2D) materials with a thickness on the scale of nanometers. With the help of the BDAT, we measured the GH shift and IF shift of graphene with different thicknesses. We found that the s-polarized light has a strong absorption effect in graphene with a thickness of approximately 15 nm, causing abnormal GH and IF shifts. This abnormal GH shift combined with the BDAT can be applied to detect changes in the refractive index, with a sensitivity of up to 9.5 x 10(-8) per reflective index unit. The BDAT holds promise as the most widespread means of displacement measurement, uncovering the properties of 2D materials and enhancing their application potential.