(INVITED)Planar microcavities: Materials and processing for light control

Microcavities are a class of optical structures providing a versatile approach to engineering light matter interactions. In light of recent developments in materials processing technologies, in particular for organic and hybrid ones, and of the need for high efficiency optical systems, there has been extensive innovation and improvement in their design and realization leading to a multitude of structures and materials. Among these, closed multi-material microcavities or microresonators based on the effect of dielectric contrast have been attractive for their low losses, applicability in a wide spectral range, and customizability. High-dielectric contrast microcavities based on distributed Bragg reflectors have been adapted early on for their highly controlled fabrication and strong light confinement and proved to be essential in current technologies including lasers and light emitting diodes. In this review, we map their evolution from planar one-dimensional inorganic structures to more sophisticated designs incorporating various categories of organic and hybrid materials. Additionally, we provide an overview of state-of-the-art developments and limitations of this class of structures.