Nonlinear optical behavior of confined electrons under torsion and magnetic fields

We investigate the linear and nonlinear optical properties of electrons in a torsion-bearing semiconductor nanowire, modeled by a non-Euclidean metric encoding a uniform density of screw dislocations. In this geometric framework, the confinement emerges naturally as a radial effective potential. We analytically determine the energy spectrum and wave functions to compute the optical absorption coefficients and refractive index changes, including third-order nonlinear contributions. The results demonstrate that torsion, Aharonov–Bohm flux, and external magnetic fields significantly modify the optical response, leading to tunable resonances and dispersive behavior. This highlights the potential of geometric engineering for controlling nonlinear optical phenomena in twisted nanostructures.