Exploiting the laws of quantum mechanics for the benefit of society in the so-called "second quantum revolution" is one of the greatest challenges of 21st-century physics. With such capability, we would be able to make quantum technologies that allow secure communication, quantum computers that outperform supercomputers, and quantum simulators of complex physical problems inaccessible to solve with current computing technologies. In order for this to happen, we need to efficiently produce particles, control their states, detect them and make them interact strongly with each other. Photons, quantum particles of light, are one of the most promising building blocks of future quantum technologies. We can easily detect and control their states and we can efficiently produce them individually. However, making them interact strongly to build a large quantum network is a notoriously difficult task because photons do not interact at low energies. To make them interact indirectly, we can hybridise them with other particles that do strongly interact and form new particles called 'polaritons'. In this project, we aim to hybridise photons with Rydberg excitons. Rydberg excitons are highly excited electron-hole pairs that can span macroscopic dimensions. Because of their macroscopic dimensions they strongly repel each other. The semiconductor device that we have chosen for hybridisation is a 2-dimensional semiconductor microcavity formed by two highly reflective mirrors encompassing nanocrystals and thin films of cuprous oxide. Photons confined in the microcavity strongly couple to Rydberg excitons in cuprous oxide to form Rydberg polaritons. The Rydberg polaritons interaction strength will be orders of magnitude higher than the current microcavity polaritons. This breakthrough will allow us to explore quantum optics at the single-particle limit and form 2-dimensional networks of strongly correlated photons for future single-photon switches and quantum simulators.