Transmitting, emitting and controlling light: Processing of transparent ceramics using current-activated pressure-assisted densification

We review recent advances in using current-activated pressure-assisted densification (CAPAD) for fabricating polycrystalline ceramics that are transparent to visible and infrared light. In addition, we discuss important one-dimensional (vacancies), two-dimensional (grain boundaries) and three-dimensional (pores) defects that can affect optical properties. We pay special attention to procedures whereby the benefits of CAPAD can be used to ensure the precise control of microstructure that facilitates transparency and other functionalities.