Tunable induced transparency of graphene-assisted micro-resonators, nonreciprocal transmission, fast and slow light

We theoretically analyze optically induced transparency and the related slowing of light in a graphene-assisted coupled micro-resonators. One of the resonators provides gain by optical pumping via Raman scattering and other one contributes symmetric loss induced by graphene layers. The absorption and dispersion profile of the probe field are illustrated in detail under different system parameters. The intra-cavity field intensities suffer revival and suppression which can be tuned by graphene induced loss. The present system shows nonreciprocal transmission. The maximum value of the isolation ratio reaches about 16 dB under optimization of different system parameters. The phase of the output field exhibits both anomalous and normal dispersion and this confirms the group velocity is both negative and positive. The present system shows slow-to-fast light propagation. This is useful for optical isolation, optical sensing and ultra-fast signal processing. These findings supply a platform for controlling light propagation using nano-fabricated devices.