Nonreciprocal Goos-Hänchen shift in a Dirac semimetal based asymmetric photonic crystal structure

The generation and control of the Goos-Hänchen (GH) shift is a vital step toward its realistic applications, but investigations have mainly been limited to the directional-dependent ones; i.e., the GH shift is reciprocal for two opposite propagating directions. Here, by designing the asymmetrical multilayered structure with three-dimensional bulky Dirac semimetal (BDS) films, we theoretically confirm the footprint of the pronounced directional-dependent GH shift, and that it can be switched by the Fermi energy of the BDS. In addition to this electric field induced switching, the period numbers of the unit cells in the asymmetrical structure can also modulate the directional-dependent GH shift. The asymmetrical feature of the multilayered structure dominantly causes the emergence of the directional-dependent GH shift. Our discovery related to the directional-dependent GH shift constitutes an important ingredient for directional-dependent optophotonic devices such as directional sensors, optical switches, and detectors.