Single-Mode Magnon-Polariton Lasing and Amplification Controlled by Dissipative Coupling

We demonstrate single-mode lasing of magnon polaritons in a cavity magnonic system enabled by dissipative coupling between two passive modes, microwave cavity mode and magnon mode in a ferrimagnetic spin ensemble. The cavity mode is partially compensated through a feedback circuit, which reduces its linewidth but retains its dissipative nature. By tuning the compensation strength and dissipative coupling strength, we reach a system cooperativity of unity, marking the lasing threshold and the formation of a zero-linewidth polariton mode. This mode also corresponds to a perfect Friedrich-Wintgen bound state in the continuum. Further increase of the cooperativity drives the system into the strong dissipative coupling regime, where magnon-polariton amplification arises between two real-frequency scattering poles. These results reveal that dissipative coupling cooperativity carries a clear physical meaning and serves as a key parameter for controlling phase transitions. Dissipative coupling offers an alternative paradigm for tailoring light-matter interactions, paving the way for advances in both information processing and quantum technologies.