This study investigates the optical properties of carbon nanotubes (CNTs) and silicene nanotubes (SiNTs) under the influence of external magnetic fields, focusing on their linear and nonlinear optical responses. A tight-binding model is employed to analyze the effects of magnetic fields on the electronic band structure, dipole matrix elements, and various optical susceptibilities of zigzag CNTs and SiNTs. The results reveal significant magnetic field-induced modifications in both linear and nonlinear optical spectra. Key findings include the splitting of optical peaks, red-shifting of spectral features, and distinct differences between CNTs and SiNTs in their response to magnetic fields. Notably, SiNTs consistently exhibit lower-energy spectral features and enhanced magnetic field sensitivity compared to CNTs. The magnetic field serves as an effective parameter for tuning the position, intensity, and number of peaks in various optical susceptibilities, including linear susceptibility, quadratic electro-optic (DC Kerr) response, and third-harmonic generation. These findings provide valuable insights into the magneto-optical properties of selected nanostructures and highlight the potential of SiNTs for applications in tunable nonlinear optical devices and magneto-optical sensors.
