Effects of applied external fields on the nonlinear optical rectification, second, and third-harmonic generation in an asymmetrical semi exponential quantum well

Abstract

The asymmetric potential profiles are focus of interest for researchers who study semiconductor optoelectronic devices. Therefore, in this study, the effects of structure parameters (σ and V0) and applied external perturbations such as electric (F), magnetic (B), and nonresonant monochromatic intense laser field on the nonlinear optical properties of the asymmetric semi-exponential quantum well (ASEQW) are theoretically investigated. The nonlinear optical rectification (NOR), second-harmonic generation (SHG), and third harmonic generation (THG) coefficients of ASEQW structure are considered. Theoretical investigations on these optical coefficients are performed in two steps. Step 1: The energy eigenvalues and eigenfunctions of a confined single electron in the ASEQW are obtained by using the diagonalization method within the framework of the effective mass and parabolic band approaches. Step 2: The compact density matrix approximation has been used to calculate the coefficients of the nonlinear optical response in the structure. The numerical results reveal that the structural parameters and external fields change the confinement potential profile of the system, and these effects significantly affect the NOR, SHG, and THG coefficients based on intersubband (intraband or subband) transitions in a low-dimensional quantum system. As a result, the amplitude and peak position of these optical coefficients are easily controlled by the applied external fields and can be adjusted according to the purpose.