  We demonstrate theoretically the Fano resonance and the conversion from fast
to slow light in a hybrid quantum dot-semiconductor/superconductor ring device,
where the QD is coupled to a pair of MFs appearing in the hybrid S/S ring
device. The absorption spectra of the weak probe field can exhibit a series of
asymmetric Fano line shapes and their related propagation properties such as
fast and slow light effects are investigated based on the hybrid system for
suitable parametric regimes. The positions of the Fano resonances can be
determined by the parameters, such as different detuning regimes and QD-MFs
coupling strengths. Further, the transparency windows (the absorption dip
approaches zero) in the probe absorption spectra are accompanied by the rapid
dispersion, which indicates the slow or fast light effect, and tunable
fast-to-slow light propagation (or vice versa) can be achieved by controlling
different parameter regimes. Our study may provide an all-optical means to
investigate MFs and open up promising applications in quantum information
processing based on MFs in solid state devices.
