Optical conductivity of SrTiO$_3$ based interfaces

Since the discovery of a high mobility two-dimensional electron gas at the interface of LaAlO$_{3}$/SrTiO$_{3}$, there has been a large scientific effort to understand the properties of perovskite interfaces. Naturally, this effort has focused on magneto-transport and photoemission studies. Here we use the Kubo formalism to study the optical conductivity of SrTiO$_3$ based interfaces and discuss its implications on the underlying physical properties of these systems. In particular, the response to light polarized in- and out-of-plane will be contrasted.