Giant tunable Goos–Hänchen shifts based on surface plasmon resonance with Dirac semimetal films

Abstract

Surface plasmon resonance (SPR) with bulk Dirac semimetals (BDS) has been proposed to enhance the Goos-Hänchen (GH) shift. It is found that large positive and negative GH shift can be obtained by adjusting the thickness of BDS film, and the GH shift is very sensitive to the Fermi level of BDS film. By changing the Fermi level of BDS film, we can get a controllable negative GH shift. The largest GH shift of the proposed configuration as large as 361.4 times of the incident wavelength has be obtained. Compared with the traditional SPR structure, the GH shift is increased by nearly 13.4 times, which indicates that BDS is expected to replace the traditional SPR structure to excite the stronger SPR. Finally, the numerical simulation results further verify that the giant shift can be obtained by finite width Gaussian beam in our proposed calculation. Based on this giant and controllable GH shift, it may have potential applications in tunable sensors, switches, filters, and other devices.