Active control of Imbert-Fedorov shifts with graphene-coated chiral metamaterials

•IF shifts are actively tuned by graphene's chemical potential and CMM's chirality.•IF shifts are controlled evidently near pseudo-Brewster angle for p-polarized beam.•High-permittivity dielectric or low-chirality CMM causes a broad shift modulation.•Graphene reduces the SIF shift, but it plays a crucial role in the shift modulation.

We propose a method for controlling the Imbert-Fedorov (IF) shifts of a reflected beam at a graphene-coated chiral metamaterial (CMM) interface, where graphene's chemical potential, the CMM's chirality parameter and the permittivity of dielectric at interface serve as external tunable stimuli to control the IF shifts. The spatial IF (SIF) shift and angular IF (AIF) shift are formulated by the reflection coefficients. The numerical results indicate that for p-polarized incident beam, the IF shifts can be controlled efficiently near the pseudo-Brewster angle through the chemical potential, and that both the high-permittivity dielectric and low-chirality CMM can bring about a broad shift modulation. Actually, the existence of graphene reduces the SIF shifts, but it can play a crucial role in the shift modulation. The above results might be helpful in exploiting various tunable terahertz-wave devices.