Structure and Field Dependence of Second Harmonic Generation in Asymmetric Three‐Step Quantum Well

The structure of three‐step quantum well is receiving attention to improve the response of nonlinear optical coefficients. Here we investigate second harmonic generation produced in an asymmetric three‐step quantum well by exploiting both structural parameters and external fields for maximizing the value of response aiming at elucidating the value of parameter regulation. Regarding structural parameters, variations in central barrier thickness and well width induce multiple resonance peaks in the second‐order nonlinear susceptibility, attributed to quantum confinement effects and energy level spacing modifications. Electric fields induce Stark shifts that alter wavefunction overlap and dipole matrix elements, while magnetic fields introduce Landau quantization that interacts with structural asymmetry to generate additional nonlinear polarization. The SHG induced by asymmetric three‐step quantum well is theoretically studied for the first time, demonstrating that the resonance peak of the second harmonic coefficient changes significantly by adjusting the parameters within a certain range. Our findings can be of interest in parameter design and experimental applications of optoelectronic devices for the selection of the more appropriate nonlinear optical configuration.