A Janus Logic Gate with Sensing Function

A layered metastructure (LM) formed by a quasi-periodic arrangement of graphene and isotropic dielectric mediums, which can realize the functions of the tunable logic gate and refractive index (RI) sensing based on spin Hall effect (SHE), is theoretically studied. The asymmetric arrangement of the mediums and the increased angle of the incident electromagnetic waves (EWs) equip the LM with Janus feature. Through the modulation of the graphene chemical potential, the sharp absorption peak (AP) in the terahertz (THz) range can be obtained, and then the AP can be used to implement NOT logic and OR logic respectively corresponding to the forward and backward scales. By locating the incident angle of light corresponding to the SHE displacement peak, the linear measurement relationship between RI and SHE angle can be realized, and the widest RI measurement range is 1-1.4 with the angles changing from 21.88 degrees to 61.84 degrees. Additionally, a good linear range can be achieved, owning the optimum sensitivity (S) up to 153.5 degrees RIU-1. The RI sensing still strictly follows the logic functions of the forward NOT and backward OR via adjusting the chemical potential of graphene and discriminating the peak value of SHE displacement.

Automated summary

A layered metastructure consisting of graphene and isotropic dielectric mediums is studied theoretically, which can achieve the functions of tunable logic gate and refractive index sensing based on spin Hall effect. The asymmetric arrangement of the mediums and the increased angle of the incident electromagnetic waves give the metastructure Janus feature. By adjusting the chemical potential of graphene, a sharp absorption peak in the terahertz range can be obtained, corresponding to the forward and backward scales of NOT logic and OR logic, respectively. By locating the incident angle of light corresponding to the SHE displacement peak, a linear measurement relationship between refractive index and SHE angle can be realized with a wide measurement range of 1-1.4 and optimum sensitivity up to 153.5 degrees RIU-1. The refractive index sensing still strictly follows the logic functions of forward NOT and backward OR by adjusting the chemical potential of graphene and discerning the peak value of SHE displacement.