Magnetic field control of absorption coefficient and group index in an impurity doped quantum disc

The electronic properties and optical characteristics – absorption coefficient, refractive index and group index – in an impurity doped pseudo-harmonic quantum disc subjected to an applied magnetic field are investigated. Numerical calculations are performed using the exact diagonalization technique and the compact density-matrix formalism. It is found that the chosen structure could be switched between a lambda-type and a ladder-type configuration by a proper tailoring of the magnetic field strength. Furthermore, the absorption profile and the associated slow light frequency range can be controlled not only by varying the control field amplitude and its detuning but also by changing the impurity position and the magnetic field strength.