Improved control over the interaction between light and matter has been a driving force of technology since the invention of the laser in the 1960s. The strongest interactions (and most interesting physics) are observed when both photons and electrons are confined to small physical volumes. By placing photonic nanomaterials into optical microcavities we can modify the 'internal' electronic properties of the materials and observe changes in their behaviour which can be exploited for a wide range of applications from IT to healthcare and security.