Effects of dopant interlayer distance, magnetic field and electric field on nonlinear optical rectification, second and third harmonic generation in double δ-doped quantum wells

The influence of the variation in separation between the doped layers on key optical properties, such as the nonlinear rectification coefficient (NOR), the second harmonic generation coefficient (SHG), and the third harmonic generation coefficient (THG), has been investigated. A symmetric double V-shaped potential model was utilized, where an external electric field was applied to break the symmetry and enhance the second-order susceptibility. In this context, the analysis of the combined effects of both electric and magnetic fields on these nonlinear optical properties is included. This study focuses on a double delta-doped quantum well structure (DDDQW), composed of $n$-type GaAs, with identical doping densities in both dopant layers. The electronic structure of the system was derived using the finite-difference method employing the Thomas–Fermi, effective mass, and parabolic band approximations. Our results reveal that altering the distance between dopant layers and varying the external electric and magnetic fields modifies both the position and magnitude of the maximum peaks of the NOR, SHG, and THG coefficients. These findings have implications for the optoelectronics industry, contributing to the design and development of materials and devices capable of advanced light manipulation and detection within specific frequency ranges in the terahertz domain.