Authors: Michele Tamagnone, Arya Fallahi, Juan R. Mosig, and Julien Perruisseau-Carrier
Source: FERMAT, Volume 11, Communications 15, Sep_Oct, 2015
Abstract: The potential of graphene for use in non-reciprocal terahertz applications was evidenced by recent demonstrations of the Faraday rotators and microwave isolators. These promising yet preliminary results raise crucial questions: what is the optimal performance achievable by more complex designs using multilayer structures, graphene patterning, metal additions, or a combination of these approaches, and can this optimum design be achieved in practice? We provide an answer to these questions by showing the existence of an upper bound on the performances of passive graphene non reciprocal devices, and we show optimal designs able to reach these performances. The bound depends uniquely on the conductivity of graphene under magnetic bias, and hence enables an estimation of the best possible performances prior to any design. We believe that these results constitute an important roadmap for future devices based on graphene's non-reciprocity.
Keywords: graphene, isolator, gyrator, non-reciprocity, terahertz.
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Non-reciprocal devices based on magnetostatically biased graphene: state of art and theoretical limits