Topological insulators are currently a main focus of condensed matter research. They have a unique property in which the bulk of the material acts as an insulator, while the surface states display metallic behavior. Using infrared, optical and magneto-optical spectroscopy, we have studied 3D topological insulators Bi2Se3, Bi2Te3, Sb2Te3 to understand their optical properties. The measurements were carried out using a Fourier Transform Infrared Spectrometer (FTIR) and an ultraviolet - visible spectrometer at varying temperatures ranging from 5 Kelvin to 300 Kelvin and at varying magnetic fields up to 18 Tesla.
We use the Drude - Lorentz model to replicate the experimental data of the samples allowing to gain an understanding of the physical phenomena happening in
the infrared, visible and ultraviolet regions of radiation. This understanding gives us insight on the optical properties of the materials such as charge dynamics. Results show that the temperature and magnetic eld have an effect on the charge carriers especially near the plasma frequency.