Effect of structural parameters and applied external fields on the third harmonic generation coefficient of AlGaAs/GaAs three-step quantum well

This presented work includes the first in-depth theoretical investigation of the third harmonic generation (THG) coefficients of the AlGaAs/GaAs three-step quantum well. We explore how these optical properties evolve when influenced by tunable structural parameters and various external fields, including electric, magnetic, and non-resonant intense laser fields. Firstly, we obtained the subband energy eigenvalues and eigenfunctions of the structure using the diagonalization method within the framework of the effective mass and envelope function approach. Then, we calculated the THG coefficients of the structure using the compact density matrix approximation. The obtained numerical results demonstrate that, within a certain range of structural parameter adjustments and applied external field changes, significant shifts (red or blue) occur in the resonance peak of the THG coefficient. These changes elegantly reflect the practical implications of the presented study. Finally, we discuss the optimality of the structure for a certain amount of applied external fields, which can be crucial for pre-experimental studies applications and the design of optoelectronic devices.