We theoretically study the Goos-Hänchen (GH) shifts of Gaussian beams reflected in parity-time (PT) symmetric multilayered structure coating graphene structures. And there are the exceptional points (EPs) in this structure, whose position can be adjusted by the real part of the dielectric constant and the incident angle. Moreover, we find that the value and direction of the GH shifts change significantly under different EPs, so we could control the GH shifts by the position of the EPs. When the dielectric constant is fixed, the GH shifts can also be adjusted by the Fermi energy of graphene and the period number of the PT-symmetric structure. With the increase of the period number of the PT system, the system will produce the Bragg resonance, which refers to the phenomenon of total reflection caused by the interaction between the wave and the periodic structure with a specific frequency. And at the Bragg resonance, the special GH shifts independent of the incident direction can be obtained with large reflectivity. In addition, the incident direction of the beam can also affect the GH shifts in this asymmetric structure. Our results may find great applications in highly sensitive sensors, optoelectronic switches, and all-optical devices.

We theoretically derive the expression for the Goos-Hänchen(GH) and Imbert-Fedorov(IF) shifts of the Airy beam in Dirac metamaterial. In this work, the large GH and IF shifts can be found when the Airy beam is reflected near the Dirac and Brewster angles. Compared to the Gaussian beam, the GH shifts of the Airy beam are more obvious in the vicinity of the Brewster angle. Interestingly, it is found that the ability to produce an Airy vortex beam at the Dirac point. In addition, the magnitude and the direction of the GH shifts can be controlled by the rotation angles of the Airy beam. We take advantage of this property to design a reflective optical switch based on the rotation angle-controlled GH shifts of the Dirac metamaterial. Our solutions provide the possibility to implement light-tuned optical switches. Moreover, our model can also be used to describe the GH and IF shifts generated by novel beams in other similar photonic systems

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