Infrared studies of topological insulators Bi$_2$Te$_3$, Sb$_2$Te$_3$ and Bi$_2$Se$_3$

Topological insulators are currently at the center of condensed matter physics research. These unusual materials are insulators in the bulk, but have conducting states on the surface. In this project we have used infrared spectroscopy to study the optical properties of topological insulators Bi$_2$Te$_3$, Sb$_2$Te$_3$ and Bi$_2$Se$_3$. In addition, we will report the results of magneto-optical measurements in magnetic fields up to 18 Tesla. Our results reveal unconventional charge dynamics and demonstrate the potential of infrared spectroscopy to provide insight into the unique properties of these novel materials.