We discuss novel electromagnetic effects in topological metamaterial and in complex birefringent meta material. In particular, we discuss the creation of novel topology using meta-material geometry., We also discuss three-dimensional meta-materials with balanced gain and loss for the purpose of achieving arbitrary control of a pair of polarization states.
We show that dynamic refractive index modulation provides a route towards non-reciprocal topological photonics. In particular, the phase of the modulation provides an effective gauge field for photons that breaks time-reversal symmetry, and can be used to create a wide range of topological effects, in both real space as well as in spaces that involve a synthetic frequency dimension. These topological effects are pointing to new capabilities for controlling the properties of light.