By developing a gain-embedded cavity magnonics platform, we create gain-driven polariton (GDP) that is activated by an amplified electromagnetic field. Distinct effects of gain-driven light-matter interaction, such as polariton auto-oscillations, polariton phase singularity, self-selection of a polariton bright mode, and gain-induced magnon-photon synchronization, are theoretically studied and experimentally manifested. Utilizing the gain-sustained photon coherence of the GDP, we demonstrate polariton-based coherent microwave amplication (~ 40 dB) and achieve high-quality coherent microwave emission (Q > 10^9).
@article{arxiv.2302.08904,
title = {Coherent Microwave Emission of a Gain-Driven Polariton},
author = {Bimu Yao and Y. S. Gui and J. W. Rao and Y. H. Zhang and Wei Lu and C. -M. Hu},
journal= {arXiv preprint arXiv:2302.08904},
year = {2023}
}