Variation of refractive index of a hydrogenic impurity in a parabolic quantum well

In the present work, the variation of refractive index (linear, non-linear and total) of a hydrogenic impurity in a Parabolic Quantum Well (PQW), composed of GaAs/Ga1-xAlxAs, associated with ground and first excited states are theoretically calculated variationally as a function of photon energy, well width and Al concentration. It is observed that (i) linear, non-linear and total refractive index changes (RIC) show less response to incident photon energy beyond 25 meV; (ii) linear RIC is less significant for photon energies < 5 meV and > 25 meV, but non-linear RIC shows a crossover at 5 meV, for all Al concentrations; (iii) linear, non-linear and total RIC shifts towards lower energies as L increases; (iv) all components of RIC show an indifferent behaviour with photon energy for L = 10 nm. These results show that well width, Al concentration and photon energy strongly affect RIC.