Optical rectification and second harmonic generation in different shape GaAs/AlGaAs double quantum wells under electric and magnetic fields

In this study, under the influence of electric field (F) and magnetic field (B), the energy levels, electron probability distributions, dipole matrix moment elements (DMMEs), nonlinear optical rectification (NOR) and second harmonic generation (SHG) coefficients were calculated for GaAs/AlGaAs double square quantum wells (DSQW), double graded quantum wells (DGQW) and double parabolic quantum wells (DPQW) with varying well widths. The finite element method under the effective mass approximation was used for all the calculations. In all the quantum well models, the application of electric field (F) and magnetic field (B) induced blue and red shifts in the optical spectrum. It was observed that the NOR and SHG coefficients are tunable across a wide energy range for all quantum well models. Additionally, the intensity of these coefficients was found to be adjustable for each quantum well model. The tunability was influenced by the type of quantum well model and the values of the applied F and B fields. Considering these factors, it is suggested that in DSQW, DGQW, or DPQW potentials, the optical and electronic properties can be modified through the application of F and B fields, which could be explored for designing semiconductor optoelectronic devices.