Figure 1: Structure and principle of operation of the proposed isolator.

(a,b) 3D view and cross-section of the proposed isolator. The behaviour with respect to circularly polarized light is shown. Incident LHCP terahertz waves are reflected as RHCP by the isolator, while incident RHCP waves are absorbed. (c) Magnetic field induced splitting of σ_CW and σ_CCW as a function of the bias B (f=3 THz and 8 THz, μ_c=0.53 eV, τ=35 fs, T=290 K) computed using the Kubo formula. The real part of the equivalent conductivity for the clockwise and counter-clockwise cases is shown for monolayer graphene and compared with multiples of the free space impedance η. In yellow is the area of interest for the design. (d) Simulation of the reflection coefficients for wave converted from right-handed to left-handed or vice-versa. Two working points are observed, however, the direction of the isolation in the second one is reversed. Reflection coefficients expressed in dB follow the rule 20 log₁₀ Γ consistently with the definition of Γ in terms of reflected field amplitude.