2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/115815We consider parametric interactions of laser pulses in a coherent macroscopic ensemble of resonant atoms, which are possible in the strong coupling regime of light-matter interaction. The spectrum condensation (lasing at collective vacuum Rabi sidebands) was studied in an active cavity configuration. Parametric interactions under the strong light-matter coupling were proved even in free space. In contrast to bichromatic beats in a cavity, they were shown to appear due to interference between polaritonic wave packets of different group velocities.4 pages, 2 figuresQuantum PhysicsOpticstext