Microcavity exciton-polaritons are hybrid part-light part-matter quasiparticles that result from near resonant, non-dissipative energy exchange between excitons and modes of a confined electromagnetic field, in a regime known as strong light-matter coupling. In this regime, the energetics of the system can no longer be described by distinct light and matter excitations but instead by hybrid quasiparticles with featured properties from both: the upper and lower excitonpolaritons . Due to their mixed light-matter nature, polaritons inherit a low effective mass from light, and notable interactions from their matter constituent. These hybrid properties give them the ability to spontaneously form quantum phases with macroscopic coherence known as condensates . Polariton condensates are at the forefront of emergent classical and quantum technologies, acting as low-threshold lasers , optical logical gates and quantum bits for quantum information technology .